What would I do? (note though some of these ideas have been mentioned upthread, I'll hit 'em again...)
Well, I've got three years; and I'm stuck with having to finish the roll-out of 5.5e as it's too far along in the process to bail out and rethink. So, out comes 5.5e along with the other already-scheduled releases.
But while that's happening, I'm getting people started on other projects:
--- lock in the CC/OGL licence and expand it to all editions (and see below re 4e)
--- try to get a Game of Thrones tie-in or license, make that the new Birthright, and release it as something like "Birthright: Game of Thrones"
--- get another movie in the works (if one isn't already) with hopes it'll hit the theatres before my three years is up
--- redesign and release a second version of D&D based on BX/1e, and have it in the market side-along with 5.5e (and make two-way conversion guides freely available); this both to get our cut of the OSR market and to show we haven't forgotten our roots
--- make D&D, both as game and company, a front-and-centre presence at every significant live gaming convention
--- reboot Dragon magazine as a bi-monthly paper publication and get it into mainstream distribution channels such that it appears in every local bookstore as well as the FLGSes; open some space in it up to outside writers and-or columnists
--- go back to short-form stand-alone adventure modules for both 5.5e and the "new" old-school D&D, try to have one issued in each month that there is not a Dragon magazine (thus, each month sees either an adventure or a magazine come out)
--- both the magazines and adventures would be digitally available but only after a month or so delay; if you want it first, you gotta get it on paper
--- team up with Chessex (or Lou Zocchi?) for a line of good-quality "official D&D dice" (and maybe make their use mandatory at AL tables?)
--- team up with an existing VTT outfit (roll20? Foundry? whoever) on an exclusive deal to provide official online play access to both in-print versions of the game as well as all out-of-print versions; this would be far cheaper than designing and coding our own in-house VTT
--- set up a proper discussion and community forum, free of charge to the user; either on our own or in tandem with the VTT outfit - and then listen to what's said on that forum and interact with the posters there
--- cut 4e loose and wash our hands of it, either by selling its rights to someone or putting it in the public domain as far as we can
--- emphasize the in-person social aspect of D&D and use that in the marketing
--- this one might take longer than 3 years to fully realize, but: look into starting first one, then a chain of gaming cafes, perhaps tied with other pre-existing libraries or rec facilities; some could even be FLGSes we buy out and remodel into gaming cafes and retail outlets
--- this would certainly take longer than 3 years to fully realize: take 5e, 5.5e, and community input and put together a final "modern" edition; at the same time take the "new" old-school edition, various OSR versions, our own old editions, and comminity input and put together a final "old-school" edition.
How does this make any profit before my three years are up? Good question. Much would depend on the movie, but there's some profit to be had in the minor pieces (magazines, adventures, dice); and the old-school edition would likely enough start with a sales peak even if it then dropped off later. Also, there'd be money coming from whatever deal we struck with the VTT provider. A wild card would be the GoT-Birthright piece; it'd either sell like hotcakes or massively bomb, there'd be no middle ground on that one.
