Apparently this new game was just recently announced publicly. See also the publisher's website. I liked Heinsoo's work with D&D 4th Edition, so I'll be interested in seeing what kind of game he comes up with independent of the brand (and WotC). An old-school D&D aesthetic with elements from modern story games (which I haven't played and I'm cautiously intrigued by) certainly sounds interesting. Not sure how directly it will compete with 5E/D&DNext, but if nothing else it's good to have an "alternative" to check out.
Not much else to say without more details, but I'll be watching to see how this develops.