The List of Stages that I believe are good/okay for tourneys and such (To clear up from what I was saying before):
Final Destination / Omega Palutena's Temple
Battlefield / Miiverse
Smashville
Town & City
Lylat Cruise
Halberd
Pokemon Stadium 2
Delfino Plaza
Skyloft
Kongo Jungle 64
Duck Hunt
Wuhu Island
Custom Stages (That are based on existing stages)
Big Battlefield
Windy Hill Zone
Castle Siege
Luigi's Mansion
These are in no order pretty much, just saying.
Explanations:
I prefer Battlefield and Smashville over Final Destination in this game, however, it's not really relevant as they are the best 3 stages in the game (at least to my opinion). I would easily rate SV a 10.0, BF a 9.8, and FD a 9.5. Final Destination is just camped a lot in this game as we all should know by now with For Glory. Projectiles dominate a lot of players and can be a bit annoying to get past for higher level players.
Town & City I like a lot, but it just doesn't do it as well as Smashville. Very good stage though, however some platforms do feel a bit high up.
Lylat Cruise is both a hated and loved stage by many and I am right down the middle. Yes it's hard to recover with some characters on it due to it's below-stage layout, but it also gives us a really nice layout overall for characters with short jump heights.
Delfino Plaza and Skyloft are both good, Skyloft has 2 cases where the background intrudes into the stage, however this is more noticeably there than in Mario Circuit (MK8). Delfino's as good as it, at least to me, but I may become more of a Skyloft fan, as it HAS been growing on me the more I play it.
Pokemon Stadium 2, again, I wouldn't MIND playing on this stage but I can see why people don't like it. The transformations don't happen for a while and aren't there for long, but they are very annoying and with almost all of them it's just better for both players to sit and camp until it goes back to normal.
Halberd is a stage I like and think deserves more credit. I've seen some people complain about Captain Falcon's grab release at the start of this stage, and to them, I say to mash harder. There are hazards when the initial layout lands, however I think they are pretty avoidable. Sometimes your opponent will use them to pressure you enough and kill you, so I can see why some people don't like it.
Kongo Jungle is a stage I love a lot but is discredited by a lot as well. I think the stage is great, but I understand the complaints. The barrel is weird and maybe the platform placement could be better. But I don't think it should be removed from lists for it.
Wuhu Island is fun and a good stage. That is all.
Big Battlefield and Windy Hill Zone both have the issue of being large, but again, this is a list of stages I would be okay with playing on. Not necessarily would agree with.
Castle Siege, oh boy. Yes I don't like this stage and I really think more people should be removing it from their lists, however, I will play on it when it's needed. This stage's second transformation just makes me want to vomit. Statues, 2 walkoff angles, ugh. I like the other 2 but this one is just so bad.
Luigi's Mansion is another one of those stages that I'm literally just "okay" with and nothing more. :3
Custom Stages based off of Wario Ware's initial room, Pokemon Stadium's non-transformed design, and stuff similar I am okay with. I love making new custom stages that are balanced, however, I do not like the idea of playing on a brand new stage in a tournament that someone made. We likely wouldn't get it to be popular enough to be accepted everywhere either, as that would be a longrun in itself.
As for Duck Hunt, I don't like it, but it's okay and I wouldn't mind playing on it. Simple.
Niche Stages That I would be okay with playing at a rare tourney:
Woolly World
Mario Circuit (MK8)
Gamer
Maybe the Walkoff Stages
I might as well provide some explanations:
I am not okay with Orbital Gate Assault even as a surprise tourney pick. I don't think the stage has really any competitive value, however, it may be fun between friendlies.
Mario Circuit (MK8) is one of the stages that I love to play on but do not think it's proper for a competitive environment. The background having the occasional hitbox is exceedingly easy to take advantage of if you know it's on the way. If that was removed then this would be a very good stage. Good as a surprise pick though!
Gamer and Woolly World both have layout differentation which can be annoying. In Woolly World it's not as bad because it only is flipped, while in Gamer it's either you get the good stage layout or the bad ones. However, it is a fun stage, even in competitive games, so I'm okay with it as a surprise pick.
Walkoffs are a problem, yes, however I don't mind playing on them when say it's against a friend who I know wouldn't just camp it. In a tournament I have it under "Maybe" because I know I would run into people who would walk off camp. Solid maybe, would generally be a turnoff though.
Bam, super long post but hopefully this clears some things up on my opinions of stages.