He is very capable so I'll be ok with that, but I'll rather see him work on something new.

That's like asking Judd Apatow fans how they would feel about Oliver Stone directing a Judd Apatow movie.

It's just an awkward choice.

I'm not sure. He doesn't have a huge history with story driven games... And for me that's one of the most important parts. The story has to be good. So really idk. He has the passion for the games, and that's all it takes to make a good game sometimes. I'd like to see how he would make it.

How was Fates a disappointment? It was a resounding critical and commercial success.

Well, I didn't play Fates yet (and what I've read overall from players is not that good), but Awakening was a critical and commercial success, and is still my biggest video games disappointment.... Maybe ever? 

The cost of turning a niche game into a popular one has been far too heavy for some original fans. Fire Emblem post-Awakening is basically a different series, too much changes and almost a different genre (at least a different focus, not on strategy and the battles anymore but on the eugenics/harem management). Fates Conquest is supposed to be closer to a real FE, so I'll maybe play it when it comes to EU.  But yes, I can understand why someone would call Fates a disappointment. 

Sure, I'd be willing to try a FE from Sakurai. I think he's proven to be a good game developer overall and takes his work seriously. New hands on the FE series would be interesting to try at least once.

Eeeeeeh, I mean I think it would be Ok, but no.
1-FE games take a while to do be made so him working on a FE title would mean that Smash 5 might even skip NX;
2-he has no experience in TRPG games;
3-It'd be better for him to work on old IPs that got overshadowed *cough cough Metroid or F-Zero*

It'd be a certainly interesting concept, but I think Sakurai is better suited for trying out new things and IPs, excluding Smash Bros.

Then the FE cast will be full of clones.
And will be multiplayer-focused.
With bad menus...
No, keep him far away.

Fates just wasn't as good as other Fire Emblem games imo.  It may have beeen as critical and commercial success, but I just really wasn't much of a fan of it.  My biggest complaints were its laughably bad story, bad characters(especially corrin), and the fact that even though the game was advertised as three completely different games, many maps were reused between the three games.