Fountain of Dreams is not only my favorite stage in Melee, but my favorite stage out of
all the Smash games. Everything about it is so beautiful, the visuals, the fantastic music, atmosphere, just everything. Plus it reps Kirby's Adventure (and Nightmare in Dream Land by extension) which is one of my favorite games ever. Why it hasn't been brought back is beyond me, it'd take Smashville's place as my main practice stage too.
But yeah, these are my picks for returning stages:
Yoshi's Island (Brawl)/Yoshi's Story (Melee)/Yoshi's Island (64) - I literally can't decide which one of these stages I want back. Brawl's Yoshi's Island is already in the 3DS version and I wish it made it into the Wii U one was well. It was one of my favorite stages in that game (and it's legal too!) and it had some great visuals as well. Yoshi's Story or Yoshi's Island from 64 would be really nice picks, and I thought the latter was one of the best looking stages in Smash 64. It'd make for a dope omega stage too.
New Pork City - I can understand why people hate this stage. It's super large, hard to traverse and the Ultimate Chimera was probably the bane of everybody's existence. If I were to be honest I want it back because Mother 3 needs some more love in this game, and like many have said it'd be amazing for 8-Player Smash.
Meta Crystal -
MrGame&Rock
already took the words out of my mouth, so I'll just say I'd love to see this stage back. The music getting its original version and (hopefully) good remix would highly please me.
Fourside - Just give it a good graphical revamp (pls no Google Images moon in the background like last time) and I'd be fine with it returning. Imagine if when you play the stage at night, it becomes Moonside! I think it'd look something similar
to this.
Now for new ones I'd add:
A Dr. Mario stage - Dr. Mario is one of my mains in training in Melee and one of my secondaries in Smash 4, so I like the character a lot and it'd be great to see him get his own home stage. Ever since that hoax, I've been wanting one soooo badly. It'd look so good if pulled off right.
An R.O.B. stage - I've never played any games where R.O.B. was involved, but I'd love to see our favorite Robotic Obliterating Buddy get his own home stage in some shape or form. Don't have any specific ideas but still, just something.
Cookie Country - This is my most wanted stage if Bandana Dee ever gets in. The newer Kirby games deserve some rep other than music and trophies, and taking a stage from Return to Dream Land would be a great place to start. Maybe a part of the stage could take place in the Lor Starcutter or it could be somewhere in the background but eh. Plus it'd be great to hear RtDL's fabulous music in the background. <3
Also why do y'all want Mario Bros. back? That stage is almost as awful as 75m.