I'd like them to make Smash 5 for Switch, actually having a REAL name again, (IE not just "Smash Bros. for Switch", generic crap), to in large part make up for how BLAH Smash 4 was. Smash 4 SHOULD have been better than Brawl, just as Brawl was better than Melee (mostly). Instead, it almost utterly lacked any quality single player content, with them shoehorning some crappy Mario Party type mode in, instead of having even a barebones, shitty Adv. Mode of any sort. I was very disappointed in Smash 4, honestly.
So it would be nice for them to make for that, and make a Smash 5 that is as good as Smash 4 should have been.
But on the other hand, I also feel bad for Sakurai. He tried to get away, tried to branch off and do projects he's actually interested in. Instead, he seems chained to Smash Bros., even to the detriment of his own personal health. I'm grateful/thankful he came back at Iwata's request and did Brawl, because that game was amazing. But I feel bad for the guy. He clearly wanted to move on with his career, doing other things besides Kirby and Smash Bros., and he did get that chance with Meteos and later Kid Icarus. But he seems to feel obligated to do Smash somehow. He has even stated that he does Smash for the fans, basically instead of doing games that would interest him.
I would love to see more new ideas out of Sakurai, see what he could do with more new IPs. I'd hate to see him chained to Smash forever, even if he IS the father of the series.