No full new edition ever? I mean, we are hoping here, why not go big?
And I've been looking at it, and 5e can handle most ideas I have. Including porting 4e classes, or even Star Wars Saga Edition classes. Like...you could make a 5e: Saga Editon that ignores the existing classes, and replaces them with Saga style talent based classes, and it would run fine. Same with 4e classes.
The basic foundations of 5e are really sound. As long as you present wildly divergent ideas in a package that comes as a "variant" game, I don't see why you couldn't go nuts without rebooting the game into a new edition again.
At most, give us a new printing of the updated core books with errata, the revised ranger, and some fixes to math and wording that would be too big for errata in 5e. And to that, I'd be cool with...maybe...2020?
Because it would still be playable right alongside first printing 5e, ya know?