You mean ONE game.
When Smash 64 was released, Ridley's role as an important character to be considered playable was on par with Kraid and Mother Brain. Ridley was a throwback boss, with some shades of Vile from Mega Man X, but nothing more.
When Melee was released, Super Metroid was still the basis for new stages and trophies. Ridley's importance was unchanged.
Now Brawl is where one could legitimately complain about Ridley's exclusion. The Metroid Prime Trilogy elevated Ridley from an NES throwback to a reoccurring boss with backstory, and Zero Mission helped explain Ridley's importance to Samus. But IMO, Ridley was still on the level of Gohma or Boom-Boom as a reoccurring boss.
Other M has passed, and as stupid as the game was, it elevated Ridley from a reoccurring boss into a major character, with a good chunk of the game devoted to talking about how dangerous Ridley is and how important it is to stop him. Ridley's importance to the series is now undeniable.