Big parties, like those in critical role or dimension 20 or any popular D&D cast, are boring and drag down the action. I can barely handle 4 players in my home game without getting confused, and I have to stay engaged or the game ends as I am the GM. I have no idea who 1/3 of the cast of critical role is, and I've watched a couple of episodes. Well, I sped through the fighting bits. Let Mercer describe how spooky the monsters are and watch some faces before the slog of too many people taking turns begins.

Didn't even make it to combat in dimension 20.