Exactly, the director isn't interested in making another Smash game, and I don't know if he's willing to just hand over the IP to someone else
Best bet is to make Smash 4 DX just like they did with Mario Kart. Maybe add some new characters like the Inkings from Splatoon (like how they were added in Mario Kart too) and yeah, combined content from both releases like Hyrule Warriors DE
The only difference is, Mario Kart 9 is much of a higher possibility than Smash 5 under current circumstances.
It will piss people off, but that's how it is