I think even on paper Ridley will have a hard time being a top tier character, he's got some good tools, but not enough to make up for his weaknesses, I don't think number and hitbox tweaking will fix that, it goes down to the core design of the character. I'm optimistic that even if he's awful on launch, which is much too early to tell, that balance patches will at least get him in a good spot, because although I think his moveset makes it difficult for him to be amongst the best characters in the game I also think it's an easy one to tweak enough to make him at least decent, it's not like you'd have to change the functionality of any of his moves or change his core attributes to get him there (unlike someone like Dedede or Ganondorf in Smash 4).
I plan on maining him no matter what, my most played character in Smash 4 was Jigglypuff by a landslide, so I'll manage even if he's the worst in the game. If he's just mid-tier, which is where I think he'll end up, then I'll be perfectly happy.