Well i've been playing with a few ideas for a potential HoMM 6 for quite a while, and thought i'd share them.

1: Unit Technologies.

Well the idea for this is that you can upgrade your units with different pieces of equipment, some upgrades grant improved stats, while other improve abilities or grant new abilities , and considering things here usually go for 100 of soldiers of one unit type, i thought i'd call it unit technologies.
But let me give an example or two:

Example 1: You have a regular footman, and from the barracks you are given the choice of, for a certain sum to buy all of your footmen a few different upgrades:
1: A two handed sword, would grant improved damage, but would lose shield bash and a little defence, but gain cleave.
2:Breastplate: Improved defence.
3:Mace: Lose a little iniative but gain a little more damage.

Another example could be with the priest:
He could gain a prayer book as a start, gaining him the spell bless, a small relic to boost his damage, holy incense, grants a minor magic ward to himself and those around him.

The idea would then to perhaps increase the possibilties with the units, perhaps making level 1 units a little more useful in the long run.. plus it can be used to make neutrals a little more interesting as well imagine, also these upgrades would be visually represented, so if you bought the two handed sword upgrade, the footman would have a two handed sword for example.

Again these are just examples, which i hope explain the idea, otherwise just ask for clarification.

Second Idea: Factions.
Yeah, factions within the races, got the idea by looking at the haven in HoMM 5 ToE.
The idea would be that by building certain buildings, you would grow your standing with a faction within your main race, or the race within the city, which would then grant you different bonuses.
Again taking haven as an example, if you build a lot of buildings with the zealous faction (the red ones) You would gain certain bonuses, at start a few stat boosts for the units, later as the faction standing improved, units belonging to the faction would have their growth boosted, faction specific buildings would open up, a few spells perhaps and even a feat or two even. Of course things wouldn't be going so great with the other faction, and of coruse you would be able to choose a third and neutral path in all of this.

3rd idea: Feats being visually represented.
Well this is just a more of a visual idea, again relating to ToE when fighting against the demon worshipping wizards, i kinda thought it was a bit odd they didn't look the part, and neither did any of their units who must have taken some share in it, so the idea was, that some feats would affect the hero's and his unit's look in some way, of course there would have to be feats that could do this in a sensible way. But just so again, we have things actually looking like what they are supposed to be.

Well hope you like them, and if something is not clear, point it out and i'll try to clarify.

The ideas on factions and unit technologies sound really interesting. Maybe you could, for instance, expand the Archmage's repertoire by buying him a better spellbook, or boost the Matriarch's mana by rings that expand her mana pool. The only problem is to balance this so that the units' power remains the same in equipped form when faced with other equipped units, as it would be in unequipped form. Essentially the equipment should not distort balance. It also poses a problem in Academy's case, as this is one of the faction's assets. Perhaps that could change though.

Regarding feats, it'd be cool for instance when the Warlock casted an Empowered Spell for her eyes to glow, as the icon denotes. The Hero would be even more impressive if their powers and equipment made a difference to them.

Sorry i have been so late in replying but okay:
First of all, the idea of equipment is to expand upon the units, make them more diverse, without doing a whole bunch of other stuff.. plus making level 1 monsters more viable and a diverse, plus it would also liven up the neutrals a bit.

If we were to look into an archmage i could imagine he would get a spellbook with several more spells, of course he wouldn't get more mana, spellbooks cost gold ya know Other upgrades could be an amulet that would absorb a bit of magic attacks and turn it into mana and a magical carpet that would allow him to hover and ignore terrain.

A combat mage on the other hand might get a magical gauntlet, increasing the strength of his attacks, plus allowing them to deflect and seek out another target, robes imbued with wards, making curses less effective against him, and well.. perhaps an enchanted sword, which strikes back when he is attacked, removing any melee penalty.. plus it would look cool to see it rise on it's own from the sand and strike the enemy

And for feats, sure that sounds interesting, but i had imagined that if you had fallen knight, well then the knight would look fallen and his troops would be affected by it in someway, perhaps some of the good sigilry is removed and replaced with some darker looking things, perhaps they just look gloomy or a combination of those and a few other things.

Also in connection with factions and unit techs, one could perhaps imagine that certain technologies would be faction dependant as well, i mean as haven you might unlock an upgrade which would allow for holy texts to be pinned to the armour of the vindicator if you pursue the zealous path. These would then protect against curses, on the other hand if you pursue the holy path you might unlock a cape of sorts, increasing the vindicators iniative. Stuff like that.. I'll try and get to work on a list for the haven on how it would look.. without factions counting in for now though.

Yes, the above is more or less what I had in mind too. Some really interesting ideas in there. The sword for the combat mage sounds a lot like Mordedaiken's Sword from D&D, a rather cool spell.

Well regarding the sword i had imagined it would be resting in front of him, pointy end in the ground, and then jump up and fight when it becomes necessary.

Otherwise here is a list for the whole Unit Tech idea, so far only for Haven and without factions playing in.

Peasant:
1)Militia Training: Training the drafted peasants increases their attack and health.
2)Wooden Board: wooden boards hastily made by a carpenter in the service of the lord, increases defence.
3)Holy Charms: Small blessed charms from the local church, boosts the peasants confidence, increasing their iniative.

Conscript:
1)Vambrace: By giving the Conscripts vambraces they are able to use their other arm for defence when attacked; Increases Defence
2)Harder training: By forcing a harder, but still short, training on the conscripts their speed can be increased in combat.
3)Own Gear: By having the Conscripts carry their own gear, they become cheaper as you won't need as large a supply train for them.

Enforcer:
1)BillHook: A weapon suited for larger creatures, this increases attack against them.
2)Lord's Enforcers: By upgrading their status their desire to get into battle increases, increasing iniative and damage, but lowering defence.
3)Leather Boots: By giving them proper footwear their speed increases.

Archer:
1) Longbow: By giving your archers longbows you can drastically improve their range, removing range penalties, but loose their special attack
2)Bodkin Arrows: Special Armour Piercing arrows, partially removes the defence bonus of enemy targets who are hit.
3)Hand Axe: Giving the Archers a better melee weapon gives them a better chance to survive close combat, removes melee penalties.

Marksman:
1) Pavise Shields: These large shields grant the Marksman protection against incoming arrows, but lowers their speed as they have to carry it around on the battlefield.
2)Firing Drills: Through repetitive training, the marksmen's ability to reload their crossbows improves, increasing their iniative.
3)Angel Feather Arrow: These Sacred arrows are powerful but rare, and only one is given out to each marksman, whose superior training ensures he knows how to use it well, grants a once per battle attack that strikes with luck.

Crossbowman:
1)Hollow arrows: These carefully crafted arrows are designed to shatter after hitting the target, increasing the damage.
2)Warding Amulets: Blessed by priests, these amulets grant protection against enemy spells, holding off some of the damage
3)Poison Daggers: Alchemical poisions makes the crossbowmen's daggers dangerous weapons.

Footman:
Well already know that one

Squire:
1)Hobnailed Boots: Boots crafted to ensure a better grip on the ground, thereby increasing speed.
2)Tabard of the order: Iniating the squires into a knightly order increases their morale through an improved sense of purpose and grants them a better attack through improved training.
3)Defiance: Instilling a sense of Defiance into the squires gives them another retaliatory attack in battle.

Vindicator:
1)Spiked Gauntlets: Removing the shield in trade for spiked gauntlets, the Vindicator gets an extra attack (at half damage though) at the cost of defence, which would stack with the cleave effect.
2)Blood Oath: By swearing a blood oath to defeat all foes of Elrath, the vindicators gains immunity to fear in all it's forms.(Would be shown by a parchment attached to the armour, written in blood)
3)Sword of the Avenger: A blessed sword that gives a chance for each attack for the wielder to go into a holy rage, increasing their iniative, speed and damage, but decreasing defence and you lose control over the Vindicator until the holy rage subsides.

Well i think i'll start out with these, i'll add more later on. Also these are just examples of unit techs, if you have a better idea, bring it on

I've been thinking to propose something like that for Disciples III, being more RPG-like, but it could be included in HoMM too.
So, this "additional wargear" could be designed to give not only bonuses, but, as you proposed, also penalties, making the choice a bit more difficult. For the regular Footman you could have, say, a list of Heavy Armour, Greatsword and Heavy Mace - the first increases the Defense significantly, but lowers both the Speed and Initiative, the Greatsword could increase the Attack with the same ammount it decreases the Defense and the Mace could give additional damage against heavily armored creatures (Defense value 20+ or something like that) with 40%, but lowers the general damage value with 20% (from from 3-5 to 3-4 for instance). However, I don't think any of the equpment should give additional abilities, becouse this in fact replaces the whole idea of the alternative upgrades. Speaking of the latter - the variety of the options could be increased even further by distributing the available equipment between the two upgrades - if you have 3 types of additional gear, one could be used by both of the upgraded versions, another one is available for one of the upgrades, but unavailable for the other. For instance - the Squire could carry Heavy Mace, but not Greatsword, while the Vendicator has access to the latter, but not to the former, and both can wear Heavy Armour. This brings about at least 5-6 different choices - which alternative upgrade to choose, what equipment to give it or to leave it as it is...
Damn, what a mess...

True, that'd kind of negate the whole idea of the alternates. Equipment granting bonuses to core stats is still good IMO. Maybe some of the items could carry new abilities with them anyway.

Well not tech would carry abilities anyways, but they are meant to work with that unit, and not cross over into the area of alternate upgrades, and if they do, it will be lvl 1 units, not lvl 2 that do that. The point is to make them more diverse, and allow them to become stronger also, besides it won't be every unit that will get new abilties, and also those i posted are just examples and if Ubisoft where ever to take up this idea.. probably won't go with them. I mean they could probably come up with a bunch of different techs..

Also one has to remember that i try to make the tech's unique and sensible within the context of the unit and it's background. No fun in just handing out a bunch of equipment if it isn't really special, it is sort of to be an extension of the unit, i mean if we follow my example, a fully upgraded vindicator is going to be quite different from a regular vindicator wouldn't you say ? But it would still be a vindicator.

I mean i could try with a skeleton as an example:

Skeleton:
1)Tainted Steel: By focusing unholy energies, the skeletons who are raised will have weapons that are tainted by necromantic energy, increasing their damage.
2)Grave Light: Though they do not quite understand what it is, necromancers are able to strengthen their skeletons through a strange ritual, creating a light in the ribcage that aids in holding it together.
3)Rustmail: By adding more lines into the incantation, necromancers are able to form a rusted chainmail on their rising dead, increasing their defences.

And well, i could go on. But i'd rather focus on the rest of the haven troops.