I think it's maybe hard to do, and you might lose a lot of stuff if you go to the next age, I think the developers should concentrate on different zones (khergit/nord/sarranid) with it's main advantage (nord-shields, axes, khergit good horses) and disadnantages, so f.e. sea raiders in the north, steppe bandits south, something like that, to make the map more authentic, like in singleplayer. So trading is important if you want a complete army.