I can't help but seriously respect Sakurai for all the work he's put in to each Smash game in terms of content. He's a real hard working dude. And he know's exactly what he's doing. Even some people don't realize it. He's part of the reason that the games are so fun. It has to really suck dealing with a hand injury. In a way, that's practically his lively-hood. And the Smash Bros. series really does have his style thrown into it, his own personality. The kind of thing that's hard to duplicate. I think it would be for the best if he stayed as the Smash front runner for as long as possible.
Granted, I don't agree with every choice he's made either. But you get the point. He's done a good job for the most part.
However, most popular series continue without their original creators taking the helm. Sakurai's original series, Kirby, has had plenty of great games that keep the feel of the older ones, and he wasn't directly involved with them. Miyamoto doesn't work directly with the Mario Platformers anymore if I'm not mistaken. And I think quite a few Mega Man games were made without Keiji Inafune at the helm either. I think the same situation could happen with Smash. Because it's too much of a cash cow for a company like Nintendo to just drop.
I guess another example would be the whole comic book industry. Stan Lee, for example, is the co-creator of Spider-Man, the X-Men, the Hulk and many others. But we've had plenty of writers and artist that made important contributions to their methos or whatever over the years. Like Todd McFarland or Brian Micheal Bendis.
So the real question is, if Sakurai steps down from the Smash series, who'd take his place? That's what interests me the most. Because it's very, very intriguing to me. Each developer has their own tastes when it comes to mechanics, artstyle, content and character ideas that I can't help but wonder how another set of capable hands would handle Smash Bros. Hopefully, it'd be someone Sakurai can trust with the series.
Anyways, sorry for the wall of text.