DISCLAIMER: Actually, it is hardly possible to do it, and I admit it. So sorry, but be realistic - we can only discuss it just for fun.
There was a game called "Overlord" released summer 2007. If you haven't ever played it, you can stop reading here, everything below will be boring for you.
So, the game was very cool, I enjoyed it in my school years. I downloaded it like several weeks ago and have almost done it again.
It's insanely cool! But also insanely bugged.
So, I think, Warband engine with WSE could be a perfect base to remake it. Just watch the main features we can use:
1) Much better system to lead your team - we will be able to use much more orders than in original game.
2) Weapon&Armour system that will give us much more variety.
3) Computers were much weaker in summer 2007 than they are now, when it is almost summer 2014. So, much bigger scenes and armies.
4) Better AI. Even though Warband AI makes bots do stupid things, in old games (also in Overlord) NPC did things looking even more stupid.
5) Better graphics - even though Native graphics are shit, there are mods making it better.
6) Cavalry! While M&B Native is mainly about cavalry with it's speed bonus, couched lance etc., almost any other game is about infantry. Time to fix it! Have your minions charging on donkeys!
I am waiting for your comments, guys.