Two topics here:
1) Airborne (and others)
So, what is the deal with SGB and JSF riflemen not having their final Attack purchase with random battalions? For instance, in SGB, the Airborne battalion can only buy up to Attack 2 for Riflemen, but the Mechanized I think can buy up to Attack 3 for Riflemen. You may say "Well, Airborne gets a bonus +10% attack for Riflemen," and that sounds reasonable, until you check some of the other battalions that give no bonuses to Riflemen yet don't offer Attack 3. Why? I see no reasoning for this.
2) EFEC battalions are bs.
Don't give me the l2p crap; I do well enough, and haven't lost to EFEC in the past 5 matches (The only I've found in like 2 days as far as I can remember). First of all, all EFEC battalions offer the same Attack upgrades for their Riflemen. Moreover, EFEC gets use out of its upgrades for all almost all units when they are rank Regular. With JSF and SGB, our units generally have to be Hardened to benefit from anything useful. So when we lose a unit, it means something. We have to work with trash until they rank up (after 900 fights) to Hardened, whereas EFEC can shrug off KIAs because they can get to regular and benefit from everything in a few battles. The supposed uniqueness of SGB's defense/health is worthless considering they have to be ranked up so high to benefit from the upgrades, and not to mention the health differences aren't even that noticeable. However, EFEC's speed difference, especially in their base speed + their ridiculous Mobility upgrades at low ranks, completely offsets any uniqueness of SGB.