What do you specifically do to D&D to keep the previous customers, get more new ones and bring back those that strayed?
I think I'd learn from the past year. The things I'd take away from it would be (1) Some people aren't going to like it. (2) I can't please everyone.
There's simply no way to return to the past, and I think that the past should remain dead. It's time to look at designing a good RPG, not just rehashing the same stuff that's been done for 30 years.
What do you do with races? With classes?
Get rid of classes per se. I'd prefer a scalable model that accepted archtypes, but everything is actually built from the same basics. Races are done the same way.
What do you do with fighters, rogues, clerics and wizards?
See above.
Minions?
Yes, as an option. I like the idea of minion creatures for a cinematic game.
Hit Points?
Get rid of them. Something like wound levels or condition levels are probably best. If there is anything of the last 30 years of RPG game design has taught us, it's that trying to create even a marginally realistic combat system only ends in tears.
Heal Surges?
Not needed.
Skills?
I'd try to find some sort of happy medium between a trillion specific skills and broad overarching skill classes.
Magic Items?
I'd probably get rid of the vast majority of them. In any case, I'd try to design the game so that they are a nice option but are not required to play the game.
Action points?
Yes. I think a built-in way to smooth out the randomness of die rolls is mandatory for any modern game system.
Speaking of dice? d6's only.
Do you create a starter set? Do you keep the 3 core books? What material goes into the PHB?
I do more than that. I basically create two games: one for the gearheads, one for the more casual player. The 'casual' or Basic version has a book with archetypes, pre-done spells, pre-done monsters, etc. The 'Advanced' or 'gearhead' book is a companion to that, to tell you how all that stuff is built from points or whatever.
I do not keep the 3 core books; the system redesign doesn't require dozens upon dozens of pages of repetition of 'x way to harm something'. I have one book that's maybe 100 pages for the 'basic' version; that's rules, GM advice, and a sample setting. The 'gearhead' book would be about the same size but would probably be pure crunch.
How do you plan out and execute 5th edition D&D? How do you market it?
The main book sells for about 10 bucks. For 15 bucks, you get a boxed version with an intro adventure, eight d6, and some supplemental material such as character sheets, charts, a few terrain tiles, etc. You know where the money goes that I save in printing costs over the 'three big hardbacks' model? Art and illustration. The European gaming community is smaller than ours, but their companies produce books with art and maps so pretty it'll make you cry. It's a shame, an actual shame, that we don't have consistantly great art in our books.
What else do you do to build the D&D brand?
I advertise more, and in more places. Unusual places, even. Get a movie deal. TV series. Something to get the name out there and keep it out there in people's faces.
I also bring back The Dragon as a print vehicle.
