Yeah, there are a few stages I'd really love!
Samus's N64 Stage - I don't actually remember what this was called, but I think it's the most fun iteration of the "acid comes up and burns you" gameplay that smash has ever had. I dunno, brinstar and norfair never really did it for me. Especially now that we've got Norfair as a standard platform set-up, I think it'd be nice to consider bringing back this level.
Something about how big the level was, combined with the way the platforms were set up, just made it so dang fun. This level always felt oddly cozy, because the lava could just bounce you up and save you. So it was kind of...relaxing, somehow? >_>
Great Fox from N64 - This was also just an amazing level. It was soooo big, but not in the way New Pork City was big, where it got annoying. This level always felt so fun with 4 players. I'd be 100% fine with them just replacing the Melee version of this level with its N64 version.
Bowser's Castle - I dunno what form it'd take on exactly, but doesn't Bowser deserve a stage? ; ) Have some thwomps thwomping, some lava on the floor, and if you can get the main platform to be tilty, then that's amazing.
I want some more fun stages.
All the tourney ready stages get bland after so long...
Temple is still a fan favorite since the people I play with don't go camping off in a corner.
This is how I feel, too, haha. I think right now there's an amazing distribution of fair, balanced stages, so I definitely don't want to take it too far in that direction. I think the PMBR has an appreciation for levels that are exciting and fun without being ridiculous. Like, they took out 75 m, but left in Pirate Ship. That kind of shows the kind of levels they do/don't like, I guess. (Also Pirate Ship is one of my all-time favorite levels across all the Smash games, so I'm really glad it's still in.)