I don't mean this as an attack, but I feel that, often, stages can sometimes be used as a john. Yes, there are some stages that heavily change matchups, such as Duck Hunt and Halberd (mostly in Brawl) but the thing is, stage choice always affects the matchup. Characters that have difficulty dealing with projectiles do notably worse on FD than on other stages, stages with lower ceilings make vertical KOs much deadlier and stages with high ceilings make vertical KOs far less threatening. One thing that can stagnate the meta, to an extent, is limiting stage choice too much, to the point where we're stuck on Town and City and Smashville like before. However, hazard toggle can bring about a new issue: how do we decide which stages need hazards off and which don't? Personally, I feel that stages that were already legal before hazard toggle, such as Melee's Pokémon Stadium 1 or Prism Tower, will be fine with hazards on. Of course, in the case of the former, it will probably need hazards off if the windmill works like it did in Brawl, but regardless, I think variety is a necessity, especially if Nintendo's plans to support the Switch for longer than they've supported other consoles are true (which would mean there would be a larger gap between Smash games)
If Ultimate is going to last, we should at least give a more liberal stage list a chance. If we could have custom moves available for EVO 2015, I don't think it's too unreasonable to have a larger stage list for the early competitive scene for Ultimate if not its entire competitive lifespan.