I have been playing Settlers 7 for some time now. First of all I would like to say, that it is one great game, so addictive and fun, bringing life back to the series. And so I am little saddened by the raising hatred in these more and more inactive forums.
I don´t know what are the possibilities of the next Settlers game, so as a player who is being around from the beginning of the series I was thinking about some suggestions.
Same as the Settlers had tendency to lower the quality from legendary Settlers II up to the Settlers 5 where it was no longer Settlers, so the game started getting better and better from that point up to Settlers 7.
Never was this game as close to it´s perfection as it is now, so for possible sequel to Settler, keeping these working game mechanics with Settlers 6 graphic style and bringing back the nations instead of one generic culture, plus ability to build/destroy your own military building in the sector would make the masterpiece. Settlers 7 has really nice, fantasy, fairy graphics, but keeping it more like Settlers 6 would surely help the game. It would be less chaotic, well arranged and would improve performance(which was pretty bad in S7). In Settlers you should leave more space for lots of processes running behind, there is no need to improve graphics anymore nowadays. With more realistic graphics and some various objects and textures would the great Castle Forge feature be even more fun and popular. Creating my own, realistic, majestic castle was something I always dreamed about back then and with little more options it would be great mini-game.
I personaly would also like to see ships, but can live without them.
As long time Settlers player who valued pros of every Settlers game, I along with certain game community believe that these features, supported with game editor and maybe some modding possibility would not only make the absolutely peak of the series, but also would make the game alive for a very long time. Editors and modding are guaranteed way how to keep PC game alive.
I hope my post helped the decision-making and we will see the masterpeace that is within reach.