I actually have a pretty cool idea when it comes to legal stages and moving forward with Ultimate for tournaments and all the changes we have seen. I would appreciate some sort of feedback on this if at all possible. Sorry for the length XD I went into details on some things.
So, I decided to try and do a break down of what stages I could possibly see being made legal given that we now have the Stage Hazard Toggle, Stages are chosen before choosing your fighter, and how the random stage + ban would work for tournaments IMO. (Similar stages I have grouped together due to the lack of gameplay difference between them)
First, from what we know about how the Hazard toggle will effect stages, and what we assume. We know that the toggle will turn off stage changes (As shown with the ZeRo vs MKLeo fight on Frigate Orpheon where it never flipped), turn off hazards (as shown on Willy Castle and no platforms or yellow devil), and turns off breakables (as shown on Skyworld with ZeRo vs Leffen). With this information, we can assume that means that 1) Stages that transition or change will probably stay in their initial layout even while traveling, 2) Annoying stage hazards like Jungle Japes rushing water or perhaps Norfair's lava will be turned off and disappear, 3) Some stages with breakable platforms now create permanent Caves of Life like Skyworld or Luigi's Mansion.
So, keeping this in mind, on to the list of possible legal stages from what we know so far:
Battlefield (Including Miiverse, Midgar, Yoshi's Story)
Final Destination (Possibly including Arena Ferox and Willy Caslte [unsure if walls will disqualify])
Dreamland
Yoshi's Island [64] (If Stage Hazard removes the lingering clouds, or makes them untouchable)
Brinstar [Melee] (Assuming no acid and no breakable parts of the stage)
Green Greens [Melee] (Assuming no breakable blocks drop, leaving gaps between the platforms)
Jungle Japes [Melee] (Assuming no rushing water or random fish underneath platforms) *Yay, my favorite pasttime stage could be tournament legal!*
Pokemon Stadium [both 1 & 2]
Castle Siege [Brawl]
Frigate Orpheon [Brawl]
Lylat Cruise [Brawl] (Please let there be no tilting!)
Norfair [Brawl]
Smashville [Brawl]
Warioware Inc [Brawl] (Assuming that no mini-games don't appear)
Yoshi's Island [Brawl] (Assuming platform clouds don't appear)
Find Mii [3ds] (Assuming the Dark Emperor never shows up)
Reset Bomb Forrest [3ds]
Unova Pokemon League [3ds]
Kalos Pokemon League [Wii u]
Mushroom Kingdom U [Wii u]
Town and City [Wii u]
Wuhu island [Wii u]
Skyloft [Wii u]
*Would be legal if they are confirmed*
Delfino Plaza [Brawl}
Fountain of Dreams [Melee]
Rainbow Road [3ds]
Jungle Hijinxs [Wii u]
Pyrosphere [Wii u]
That gives us an amazing 23 legal stages for Ultimate (Not counting similar gameplay stages like Midgar from Battlefield, they are grouped as 1 stage)! I did not include stages like Halberd that used to be legal due to the toggle switch. Assuming the stages stay as they initially start, Halberd would have walk-offs. I also did not include Magicant because, as others have stated, it is highly unlikely that the toggle would remove the very bottom platform, which could cause for easy camping.
This also doesn't include the Omega and Battlefield versions of stages since that is just an insane amount now.
With random stage pick + ban, the rounds at a tournament would go as followed. All illegal stages are turned off from the random stage switch, stage hazard is toggled off. Match 1, Players open up the random stage switch and each pick 1 legal stage to turn off (banning that stage), close random stage switch, and select random. Random legal stage is selected, players chose their fighters and start. Match 2, Players open up the stage switch again, winner selects 1 legal stage to turn off (aka ban), loser selects 2 legal stages to turn off (same rules apply in the event of a 3rd match), select random to chose a stage, chose their fighters and start.
In a typical best of 3 set, out of the 23 legal stages, either 5 stages will be banned (match ends 2-0) or 8 (match ends 2-1). Following the same rules above, in a best of 5 Grand Finals, either 8 stages will be banned (3-0) 11 stages (3-1) or 14 stages (3-2), leaving at minimum a whopping 9 stages still legal come the final match of a tournament. Current rule set in Smash 4, we only have 6 legal stages period. This is a very nice jump in legal stages.
Also, unlike how the stages reset in a current Smash 4 tournament set (after each match, players re-stage strike which often means they just re-strike the same stages over and over), each ban is permanent for the duration of that set. So, for instance, say player 2 bans Town and City during that banning process of game 1. Town and City would remain off for the rest of their set. This adds more weight to their ban choices.
Of course the random stage switch would be reset after each set, once again having all 23 legal stages toggled on and all illegal stages toggled off.
I am open to suggestions, but I feel like this is a good formula. It greatly increases the amount of tournament legal stages, decreases the time between matches in a set (a quick ban instead of stage striking) while still giving players some sense of control on where they don't want to fight, and it provides the flair of stages being randomly chosen each match.
