It's called Omega Mode, and I'd like to see this too. I think the Hazard Switch isn't enough to make stages more playable (just look at Silph Co or Skyward Voyage)

Omega Mode is a nice feature that could be put in but I think they should fix up the broken stages more than adding in that feature. Silph Co and Skyward Voyage are broken but they can be fixed up by making platforms bigger and other stuff. I feel like Omega mode Skyward Voyage would be a bad way to save the stage as it takes away the travel feature that makes the stage unique to others.

One thing I would like to see changed is Yoshi's stage [the ssf2 one]. I don't think it's unique in it's design or look. The stage seems like something I could easily think of and build on stage builder [if they add it]. I hope in the beta version they fix up to be more unique or swap out the stage for some other Yoshi stage [a stage based on Yoshi's Wooly World would seem like a great replacement for this]

With the announcement that Project M's retexturing Dracula's Castle into a new stage called "Delfino Secret", likely for copyright reasons, I wonder if SSF2 will follow suit...

Since we have Bowser's Castle and Dracula's Castle, I speculate they may have Ganon's Castle as well, fitting in with the villain theme.
Also, still waiting for the Station of Serenity shown from the first trailer.

That would just be a third Final Destination, which I don't really think we need. (That is, after all, why the Wi-Fi Waiting Room was taken out of the selectable stages.)

Attempt to reviving this thread:
I speculate for the Mirror Chamber to become a transforming stage, based on the Rainbow Route, Olive Ocean, Candy Constellation and Radish Ruins. Also, it should be larger.

Ill join you on this "quest": What if... there was a Retro stage in Beta that shows the 8Bit origins of the roster, then jumps to 16Bit etc. Underlined with fitting 8Bit/16Bit music.

Although we are getting a new FD, I kinda still want the old one to be in the past stages section, I really like Brawls FD

^That's why we need Project M's option of alternate stages so we can also have the Day/Night BF

I want a new distant planet style .
Because now looks like the devs copy and paste the brawl distant planet

^yes

can we have boswer's castle(project M) and a stage based off pokemon x any ( not lumiose city or kalos league)

I would love to see the Rainbow Stone Ship from Pokémon Mystery Dungeon 2, as a stage similar to Skyward Voyage, but you can't pass through the bottom. It would fly to various locations in the Hidden Land, and maybe at one point go up the side of Temporal Tower, and anyone who touches the side of Temporal Tower takes damage, kind of like the wall in Port Town Aero Drive in Brawl.

I'm in favor. Beta's deep forest BF is a little too claustrophobic-feeling for my personal tastes.

This would also have the added benefit of allowing the unintrusive return of other cut resources; Yoshi's Story 64 from v0.8 (which was superior to Yoshi's Story Melee in my opinion), Mushroom Kingdom II from v0.5 (I like MK3 and all, but I do miss this place.), Comet Observatory, Wily Castle, the old layouts for Hueco Mundo, Twilight Town, SSZ, and Saturn Valley, etc...

Though they should probably have a disclaimer so new players don't get confused. Maybe some text to the effect of;

"NOTE: This stage was deemed unfit for the final game after [version number] in [year] and replaced. It is included as a hidden option solely for the sake of nostalgia and is not intended to be counted among Super Smash Flash 2's stage selection."

on the corner of the stage menu while the ASL button is being held down or something.

I think having alternate stages like in PM but having it work like SSB4's Omega Mode would be better, that way you don't have to hold down any buttons.

I hope we get an original Mother stage.