High-quality POD for all the core rulebooks of BX, BECMI (or Rules Encyclopedia), OD&D, AD&D1-2E, and 3.5E. Get all these editions a CC SRD. All other prior edition books have a scanned version and work towards having POD editions of them all. Make a 50th anniversary case set with the core rules from OD&D to 5E as a collector's set ("D&D through the ages").
Keep the 2014 ruleset and incorporate the best-recieved quality of life changes from the latest playtests. Those playtest options that didn't make it but recieved greater than 50%, or changed things to radically put into a book of options and officially release.
Create a new DM's Starter Set with a "getting started" booklet, pre-made characters, expanded book covering up to 5th level, dice, standees, condition pogs/cards, planned adventure for 1st-3rd level, sandbox campaign booklet (set in Nentir Vale), and DM's screen (and maybe starter Monster cards, if there's room). Create a supplementary Player's Set with carry case, dice, minis (prepainted if possible), premade characters and blank sheets, player's primer and softcover PHB. Maybe a pack of starter equipment cards. Sell supplemental cards and other goodies so DMs and Players can grow into a full-blown D&D collection.
Farm D&D Beyond out to a 3rd party and party with a VTT to support the current edition and license the above editions as well (but not directly offer beyond core rulebook functionality but allow 3rd parties to convert supplements for nominal license fee).
Push to get 2-3 more D&D movies or TV shows made (my pet project would be a Dragonlance TV series covering the War of the Lance and the War of the Twins).
Develop a new version of the D&D board game series with options for DM'ed, Player Only or Solo play. Also look into a Mass Battle reinvisioning of BattleSystem - minis agnostic, but partner with Wizkids to produce "Armies in a Box" quarterly sets. Look into creating a Living Card game for D&D (perhaps pushing Dragonfire more aggressively), leaning into MtG's knowledge and expertise to make something that complements MtG (the D&D cards could be used as MtG tokens, non-tournament crossover play or somesuch).
Have a continuing line of D&D novels and comics. Use them to complement and spark interest in existing and newly released campaign worlds.
Plan a twice-a-year Campaign boxed set release. May release would be an update of a previous edition campaign set (such as Ravenloft or Dark Sun). September release would be an all-new campaign set. Go the Piazo route and create an adventure series magazine that devotes 6 issues to the campaign world in an adventure path from 1st-12th or 1st-18th+ level. Have 1-2 special end-of-the-year issue(s) that has short adventures that aren't specific to a campaign world, or revisit previously published campaign worlds (1-2 such adventures max).
That's all I can think of for now.