What if......?

[JEMC]

Fighting games are harder to make (at least the good ones) than people think. It's not only about the number of fighters and special movements, but it's also about balance to avoid having characters that are too strong or too weak. Let's not forget that the last Smash was developed by Namco, with members of the Tekken series involved.

I'd say that it's almost impossible for Retro to be working on Smash, other than a port of the WiiU/3DS game.