I agree with you, Ridely can DEFINITELY be downgraded because Smash size isn't canon. Even the Smash Bros. Series goes back on it's self at times with Ridely being only slightly bigger that Samus in Melee to being a Shadow of the Colossus Boss in Brawl. The Metroid series is also guilty of this with the Other M. From what I can see from his 3D appearances

He seems to mostly be hunched over, with the only things giving him height are the wings. Just fold those up and he takes Bowser's spot as the Hunchback Heavyweight. It's a long shot and he may still be just a boss, but my mind is still open. ( Plus Metal, Neo, or Mecha Ridely could replace his role if he fights, but I digress.)

With Ridley at that size, then he'd look awkward if being thrown by a small character like Olimar.