1. I'd stop reading the Interweb as it'd either turn me into a raving, egomaniac with little ability to take criticism or I'd become addicted to anti-depressents.
Oh... wait... forget that.
I'd revamp the editing process so that less 'obvious' errors slip through.
2. Start work on some character generation software that would make being a DM and player EASIER. I'd put a fairly high price on the initial release, but have free updates as new products are released. I'd also release some 'premium pay only' updates with some extra good stuff.
3. Create a crack team of designers, including Monte Cook, Bruce Cordell, Richard Baker, Erik Mona, and Mike Mearls and start them on pre-4e planning. Basically, looking through EVERYTHING in 3e to find out what works, what doesn't, and what the fans think.
Also, start promoting D&D more to the masses. I'd try and find ways to get D&D to appeal to more people, either by including an example DVD/CD in some games or books or by holding more events at local gamestores or malls.
4. Release a Greyhawk HC. I'd make it a BIG single release. No updates later on, but I'd release it just to give something to the Greyhawk community. Erik Mona would be the lead designer.
5. Release a single Planescape Hardcover to sate the PS fans. Make Monte Cook, James Jacobs, and Wolfgang Baur the lead designers.
6. Release a line of 'Old School Adventures' updated to 3.5.
7. Start work on having more products with OGL support. Put the Environmental books into the SRD (not including any closed content stuff...).
8. Write another 'information/optional rule book' like DMGII and UA, but include more information on how to run different game types like low-magic games and the ramifications it has on the rules. Include rules that vastly alter the flavor of the game, like completely new spellcasting systems and information on how to create races and base classes. Include much more advice. Make it OGL.
9. Publish a series of adventures for Faerun and Eberron that could take a party of adventurers from 1st to 20th level. Make each series steeped in the lore and flavor of each world. I'd have each part be connected with the previous, but include notes on how to run it as a stand-alone adventure.
Also, I'd publish more standalone adventures for generic D&D.
That's what I'd do, no matter if it's economically viable or not.