Honestly, I'm pretty much done with WotC. Not for any profound moral reasons, they've just produced all the WotCish materials that I want to buy. There are still things I want, but they're so nichey that WotC wouldn't go near them in a million years (nor should they.)
I'd like to see a tome of magic- type book that collects all the spells from all the splashbooks, dragon/dungeon magazines, published adventures and misc. supplements, plus a few new spells.
A book about running a stronghold and dominion, because that added so much to a game in OD&D (continuity, NPC interaction, a ready supply of plot-hooks, and it let the players make something, their own corner of the campaign world). And of course, mass combat. I want armies!
Rules for running nations/kingdoms, and large-scale combat. Something like Birthright minus the campaign specifics. They should include low, medium and high-magic options (i.e. everything from feudal Earth to a "kings are direct agents of gods" type of setting).