The thing on that list that I am most interested in seeing is how they deal with multiclassing. The 3e multiclassing system is the proudest nail the game has to offer. I can't think of anything that waters down character archetypes and encourages munchkinism more. Players should be encouraged to stick with their base class and allowed to diversify their talent, not the other way around (encouraged to diversify their talent and allowed to stick with their base class). They were so close to making the system flexible enough to allow you to create virtually any concept you wanted with a single class, and yet so far. Cross-class skills sucked and for that matter too many classes didn't receive enough skill points. There weren't enough feats that allowed you to diversify your talents without multiclassing. Finally, virtually every class in the game from Archivist to Wu Jen is so front-loaded as to make multiclassing way too appealing at low-levels. A 1st level wizard gains far more from a level of sorcerer than he does another level of wizard. What the hell is with that? True, he delays his progression to 2nd level spells, but the silliness is that in the short run a sorcerer level is more effective and that is just ridiculous.
Your base class needs to be appealing to stick with at every level, especially spellcasting classes. I hate to say it because the old-schooler inside me is raging at me for even thinking it, but spreading the spells out into 30 levels might be really good for the game in that respect.
