Duke John - some of the things I like are:

Shiny New Stuff - if possible, make this mod as different from RTW as possible. New interfaces, new concepts, new campaign map, all make this a new experiance.

Less Micromanagement - it sounds like armies are created very differently. I've always wanted to generate a full-fledged army in less than a year for use in game - as long as it is historically balanced (meaning painfully expensive). Also, adjusting the movement ala MTW reduces micromanagement (I would think; I don't know how you plan on doing this).

More Macromanagement - if that isn't a word, I'll patent it. I like the ideas of a bigger world with things like real, working allies, coronations, places to flee to, more dynamic-sounding families. Give me more to do than conquer, conquer, build, conquer.