First off, I like to state that I called this a long time ago and it's actually announced. My predictions with WotC have always been spot on. They're so insanely predictable.
Second, clearly 4E failed. Another thing I called when I heard just one paragraph of the changes coming to D&D with that edition.
Next, this piece of news says one thing to me: "We don't know what the hell we're doing anymore, so we're going to have you do the work for us!"
Is that what WotC has come down to with D&D? Seriously, sell the damn brand already. It's worthless in their hands. Paizo or some other company can do a much better job. Heck, White Wolf could do a much better job! They talk about unity across all editions with the gamers who are split apart from the Edition Wars by --- wait for it --- making ANOTHER edition!? Where is the logic in that?
Were I in control of D&D, I know exactly how to bring this "unity" they speak of while being very profitable. WotC, if you're reading this, please consider this suggestion. I'll also be involved in the playtest, if possible, to repeat this suggestion again.
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HOW TO FIX D&D in 3 EASY STEPS
[Number One]
Never create a new edition. Ever. Keep the 4 you have. The reason is explained below.
[Number Two]
Redistribute and release PDFs across all editions along with print-to-order hard copies of any D&D product of any edition of the game.
[Number Three]
Spread resources throughout the 4 editions, giving each their share. The newer edition receives the bigger share, and then scale down. Maybe switch it up now and then.
That's pretty much it. Keep the bases you have now and just cater to them. Rely on these 4 Editions to bring in new customers, because they will. Why?! Because they not only have reason to play D&D (because you're now supporting their edition with new material), but they're also spending money on you again in utter ecstasy to see their favorite edition "revived".
Making an edition where the customers give all the input is not going to solve jack. You're going to get too many divisive suggestions and 5E is going to be a horrendous mess. No one is going to like 5E if it doesn't incorporate most of the rules of the edition they play, it's that clear and simple.
So be simplistic and give them what they want. THEIR EDITION OF THE GAME! Clean up the first 3, have separate divisions for each edition, and just craft away, using input from the customers to determine what products you'll need to release for each edition.
That's how I'd handle it. I'd not only gain back many fans that have left, but I'll be getting new ones from 4 different styles of play which means I'll have tons of new gamers coming in.
I sometimes believe gamers really have no business sense at times. And business people seem to have no gaming sense. Mold the two together and you'll be fine.