They didn't even release the first one that long ago. This feels like it should be a "next gen" update and not a full-blown sequel, but I guess they probably need to recover costs from hiring all the voice actors and redoing all the graphics.
Well, yeah, but you can still create you own niche in the genre.
Personally, with Mario Kart and Smash, I don't need to buy any other games in these genres, but there's a still place for these games, specially if you like the characters. For instance, if they release PlayStation All Star 2, I would love to try that.
Make it Free to play. A multi-platform, free to play game. It won't be competing directly with SSB, but more with Brawlhalla, which seems to be doing pretty good for itself.