I think walk-off edges can still mess up the flow of a fight--edge camping, super early kills, etc. But the biggest reason we've avoided them in previous games was because of how someone could chaingrab an opponent and get a guaranteed kill as long as they started on a part of the stage that led straight to the walk-off. With chaingrabs gone, that massive threat dies with them.
So while permanent ones still do more harm than good, wouldn't temporary walk-offs be okay now?
Yes, you're absolutely right. That's why I think a stage like Rainbow Road with a temporary walk-off for one of its many transformations that last 7-8 seconds does not hinder the tempo of the fight enough to consider it a ban.
In perspective, I was watching Vex on Zero's stream a few days ago going over all the stages determining if a stage is "banworthy" or not. Not to write him off, but I thought the attitude presented to the viewers was disgusting. Simply picking a stage in training mode and waiting about 30 seconds to see if anything happens and outright banning it... is this the attitude you want to present to newcomers or just spectators who like to watch Smash? Though you can probably get an idea of how it can affect the match, will it really cause an unfair KO? What determines "unfair," anyway?
The diversity of stages does more good than harm, in my opinion. <3 and others make good points about the randomness in even the most simplest of games, and how even in the past when items were legal and many stages, Ken was still the dominant player. The fact we are even considering that items could be re-legalized is a good step, even if it sounds ridiculous. Having a conservative stage list hinders the metagame and player prowess and setting a certain skill gap. I couldn't believe that once in Brawl's lifetime that Corneria, Jungle Japes, Brinstar and Rainbow Cruise were all allowed, and when I watched those matches, it looked fun! Ofc, just my opinion and personal anecdote, but hey, back then I simply liked to spectate those matches. Some people that I showed them were flabbergasted, and now it's near impossible to find videos of those stages in actual tournaments.
Research and examination needs to be done. We cannot simply ban a stage because of a character's specific weakness on one stage among many that the player had prior knowledge of; see: Armada killing Falco on Mute City in Melee. One can look at Magicant and see Flying Man does a ridiculous amount of damage and knockback... but did they know he doesn't stay forever? Did they know you can KO it fairly easily? Did they know that no interference with the Flying Man makes it disappear? Probably not, they just banned the stage. And again, you need to research this more.
Will players really be hindered by the lack of pits on Mute City and Spirit Train? Are they really "unfair;" do they constitute as "luck" or "random"? I'd love to see these stages legal! They have great music, a great presentation and interesting mechanics and are barely random -- but because of small change that it doesn't have, you can't play on it? You already banned items. Why do you think the competitive community gets a bad vibe to some groups? The lack of diversity of characters was already enough (MK, Olimar, Diddy and ICs in Brawl; Fox and Falco making up 95% of all tourney attendance in Melee (not factually correct but y'know)) but now you're banning stages and the legal ones are so bland.
Pokemon Stadium 1 is the most dynamic and interesting stage in Melee, and arguably, the most interesting to see how the players and matches go and adjust their playstyles to match the stages' transformations. How is that any different from Peach's Castle in that game, which only has one easily avoidable hazard and some platform switches? Is that really random at all? And to this day, I think, there's still no reason why or how it really breaks the flow of matches and stuff. While some stages look painfully obvious with their "unfairness" like Wily's Castle, it still deserves experimentation and an explanation for being banned.
I know this post has quite a bit of rhetorical questions but people need to re-evaluate how they actually ban things, to me. This thread is going on the right track. I'm not trying to say we should legalize stages just to legalize them; they all deserve some research. Mute City looks like such a fantastic stage in Smash 3DS and yet it's not possible to play on because of this plagued way of thinking. I can watch Zero's stream for hours and while it is intersting to see the matches, the non-stop Omega stages really do get bland after a while. Maybe Sakurai was trying to prove a point? lol.