I'm pretty cruddy with Ryu, mostly because I suck at inputting the EX versions of his Specials. I'm sure I've said this before, but I've never played a Fighting-game outside of Smash, so I understand that my lack of experience with such inputs is probably the biggest reason as to why I can't reliably pull them off. Still, I'm working on getting better at inputting the EX Specials, and I hope that I'll be able to play, at the very least, a subpar Ryu someday. Despite his high learning curve, I actually find Ryu pretty fun to play. There's nothing quite like tanking a Falcon Punch and then counterattacking a second later
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That said, as bad as I am with Ryu, I'm glad he's there for those who like him. I'm sure that there are tons of people who enjoy his relatively complicated, more traditional playstyle. I think that several top-level competitive players will eventually pick Ryu up due to his competitively geared moveset and overall depth as a fighter. Who knows? Maybe some traditional Fighting-game players will decide to try Smash out because Ryu's in it. That'd be awesome!
If nothing else, it's nice to have a character in Smash that plays more traditionally. It's very interesting, and there's no one quite like Ryu on the roster. Honestly, I wouldn't mind having Ryu as a series mainstay, given how unique he is.