I haven't played F&S ... I might pick it up when it's on sale and I have the money for it. Everyone says it's a lesser game than Warband, which makes me hesitate.
I just can't wait to hear some more about M&B 2. I hope they integrate some of the best mods into it (or make them options), like Diplomacy or some of the other things in Floris and Brytenwalda. More options when interacting with people, more stuff to do in (and with) towns/villages/castles, more ways to delegate micromanagement to ministers ... love that stuff. Makes the game more interesting and easier to manage (when you have a large empire).
Any improvements to the combat would be great, but I honestly don't have complaints about M&B's combat, just the AI. Formations would be welcome. Prophesy of Pendor has a great set of scripts they call Vicky (or VI, for Virtual Intelligence) that makes the enemy act a little more realistic, assuming the enemy is an organized army -- things like trying to flank you with cavalry, or making better decisions on forming ranks / squares / wedges with troops, bracing spears to counter cavalry, sending their cavalry to hit your archers ... it isn't perfect, but it's a lot better than Native's setup and definitely more fun to fight against.