This is the biggest misconcept ever. Melee Ridley, is actually big. The camera is just playing tricks on ya.
The misconception exists on both sides of the debate.
The detractors want the supporters to believe that Ridley is actually HUGE in the Melee video. The detractors either fail to understand or intentionally ignore that, regardless of Ridley's actual size in that video, what happened is that people found an acceptable range of scale for playable Ridley in that video. People want to say "He'll look weird shrunken down" and crap like that, but it's clear those words are merely personal sentiment, and they're not shared across the board.
...But that's not all. Detractors have failed to notice the Metroid capsule Ridley is holding. Even if the capsule is at exact scale as it was in the game, it would only mean that Ridley is
slightly larger than he looks in the video. NOT "huge".
It's actually interesting... Let's consider not just the capsule itself, but the size of the metroid larva within.
As you can see: Capsule, Larva, Samus, Ridley.
Now here's a scene from Super Metroid prior to the encounter with Ridley: Larva, Samus, Scientist.
Larva, Capsule, Scientists.
And.... the Melee opening: Samus, Ridley, Capsule, Larva (barely...)
Perspective can be a really funny thing, ya know...