From what I've played and observed, these are my thoughts (read: first impressions) on the stages. 1v1, no items, final destionat-wait a second. Anyway, you get what I mean. It's like a prediction list. I am being pretty conservative about banning.
Neutral: 8
Counter-Pick: 19
Banned: 13
This doesn't add up to 41. What am I missing I can't figure it out.
Neutral
Pokemon Stadium - Melee stage. Windmill now cannot be passed through (I haven't hit it yet as I've only played Stadium twice, I wanted to try Brawl stages more >_>). Doesn't change much.
Smashville - Awesome stage. I really like this one. No hazards. Floating moving platform makes for some cool stuff that could potentially develop.
Yoshi's Island - Awesome art? >_> But seriously, it's really standard. There's that platform that comes up and goes down that reminds me of that evil cloud from Melee's Yoshi's Story stage.
Lylat Cruise - There are actually no hazards on this stage as far as I know. Seems neutral.
Frigate Orpheon - The stage flipping does almost nothing and the screeching alarm should be enough warning. Could be counter-pick.
Castle Siege - Three different formats through the match. So like Pokemon Stadium, you have the "no one character keeps the advantage the entire round" thing. As long as you stay prepared during the transitions, this stage is really neutral and fine. No stage hazards to speak of that I remember.
Battlefield - No Brainer
Final Destination - No Brainer
Counter-Pick
Delfino Plaza - no real stage hazard, set pattern I believe. Potentially neutral.
Mushroomy Kingdom - set pattern, do any characters get SEVERELY overpowered or underpowered on this stage? Walk off edges is =/ 1-2 is a bit less balanced IMO, might have to look at a ban for the stage in general. I'd say 1-2 would likely be banned at the least (go with no contest and start it again).
Rainbow Cruise - Melee stage. Was counter-pickable in Melee, neutral for a while which I disagreed with. I wouldn't say enough has changed to ban.
Mario Circuit - cars either come below or above at a set time interval and alternate. There's a TV in the background that even shows where the cars are currently. However, cars can do major damage unlike Mute City so we'll see. The layout of the stage in general just looks like it's going to make something broken.
Luigi's Mansion - I would call this stage neutral if it weren't for the fact that there's parts of the stage where the ceiling above cannot be gone through. It's a solid object. Still, nothing to ban over and a solid stage.
Pokemon Stadium 2 - Might require a ban. The stage hazards on this one are pretty **** bad. The electric stage has the conveyer belts with the person in the middle being close to unapproachable. The anti-gravity air one is murderous. The ice actually feels decent compared to the first two. Ground is fine. Requires testing. In no way neutral, but counter-pick or maybe banned.
Bridge of Eldin - Ok. I am very torn on this stage. When the middle is gone, some faster characters with fast projectiles (read: space animals) can very easily camp. However, that's gone soon. The edges are walk off =/ This doesn't seem that bad a stage but I dunno if I'd call it neutral.
Great Sea - I like this stage and feel it's really neutral, but there are some stage hazards. The bombs which you can see coming from the background do 35% per direct hit. They can be avoided and you can see them coming, but not sure how much trouble they'd cause. There's also the catapault but that is easily avoided. I believe they don't fire until a certain time after they come out. Depending on how severe people find canonball intereference, this stage could be banned. I have lost a match or two by getting hit by a canonball and then having my opponent combo that into a KO. Of course, I have really crappy peripheral vision it seems (friggin Onett ;_
Halberd - Aside from being home to the best music in the game, it's also home to lasers, bombs, and a tentacle monster. However, I've spent time on this stage and the laser is easy to avoid as it locks onto one person, then lets that person escape for a good second before hitting. No one has yet to be hit by it in a 1v1 in my group of friends. The bomb is similar, it's so slow moving you deserve to get hit if you do get hit by it. Tentacle thing does 10% and isn't much of a bother. I don't see this stage as anything worse than Brinstar in Melee. It's much better than it.
Green Greens - Melee stage. It wasn't banned in Melee although I thought of it as a pretty crappy stage. I don't think much has changed to ban it now.
Yoshi's Island Melee - I personally hate this stage. However, I think people's concensus is that it was banned in Melee due to Fox being his waveshing douche of a self with walk-off edges. This stage could be counter-pickable or banned. I guess it is fair in a way, but I honestly don't like this claustrophobic stage.
Corneria - Melee Stage. I found nothing wrong with it except for the occasional lasers in Melee, I find nothing wrong with it now. I guess Fox still has his wall infinite but I think it doesn't work for long anymore? Haven't looked into that too much. Seems to be a good counter-pick stage unless it appears Fox is too broken on it.
Onett - Melee stage. Controversial stage in Melee. It wasn't banned most of the time there so I don't see it being banned this time. Nothing's really changed. Depends on how Fox's infinite works this time around since I haven't followed that much.
Norfair - Looks horrible at first glance, but it's not THAT bad. I've heard reports you can jump over even the largest wave without going into the safespot.
Brinstar - Melee stage. Same as before. No changes. Stupid lava can be annoying but avoidable.
Green Hill Zone - This is one I'm not sure of. The resume point thingy that spins is annoying. Someone can camp near there and make it really hard for the opponent to approach. The stage seems a little small, the sides are not very far at all. Think it might be banned, might not.
Electroplankton - I thing this stage is fine. The platforms only change slightly when you or your opponent attack it. I have heard that tether recovery characters have some issue on this stage (so Olimar?). I think it's a good, solid stage though.
Pictochat - Another interesting stage that might or might not be banned. I lean towards not. There are some flames and spikes that sometimes get drawn, but that's about it and the hazard is in plain sight and not moving.
Skyworld - I hate this stage. That said, not sure if the reason I hate it warrants a ban. I don't like how you can't move up through the platforms. I really think anyone in the middle has a great advantage as your ways of approaching them are extremely limited.
Banned
Mario Bros. - No Brainer.
Spear Pillar - Sorry Dialga/Palkia/Cresselia. This is a very bad stage. You Cresselia's boomerang thingy that can easily KO flying around randomly when she's around. Palkia can invert controls, turn the stage upside down, and shoot Special Rend beam anywhere. You have Dialga who can slow down time and shoot Roar of Time anywhere. There's a cavern at the bottom which an opponent can go hide in and make approaching near impossible. Not a good stage. It's not even fun =[
Hyrule Temple - Melee Stage. Still banned. Nothing changed. I'm fairly sure Fox can still do his thing and they haven't changed that area at the bottom, although I'm not sure if that was part of the reason for the ban in the first place.
Rumble Falls - This is Icicle Mountain, less crappy, but Icicle Mountain nonetheless. I guess people could try and give it a go considering it always goes up, not down, but honestly I haven't played this one.
Jungle Japes - Melee Stage. This was a controversial counter-pick in Melee, but with the rapidly flowing water now getting the swim mechanic, this stage has been pushed over the line IMO.
72m (Donkey Kong) - This stage is horrible. Holy crap. There's no argument against it being banned so here's a fun tip for when you play it: Don't touch Donkey Kong he hurts >_>
Big Blue - Melee stage. Kill it with fire and take Crushed with it.
Port Town - This looks like a decent stage, but the problem I have with it is the cars. In Mute City, the cars could not kill. They'd damage and keep you in the air maybe, but not kill. Now, they seem to come out of nowhere and do enough knockback to KO. Not only that, they did it in a video I saw even though the player was on a platform.
New Pork City - Mele- wait a second this isn't Hyrule Temple. It's got a new skin! The stage seems even BIGGER than Hyrule Temple. There are certain characters I can see definitely abusing this to an amazing degree to stall out a match. The chimera in my opinion doesn't matter as that thing is so slow and gives so much warning you couldn't possibly get hit.
WarioWare - When I first started playing this I thought it was much better than I thought it would be. The problem is, every time you win a mini-game you get a prize - including Starman. If they took out the broken reward system I think this stage would have made a cool counter-pick, but with stars being handed out there's not much hope.
The Summit - From what I remember, this stage has some weird anti-gravity at times, the bottom edge can't be grabbed, and is slippery at most times. I guess it could be counter-pick but it seems like it'd be banned to me. I didn't like it too much but there's worse.
Distant Planet - Can't talk too much about it. This is really a first impression type thing. Good chance this could be counter-pick even. I just remember there being water on the left side. Can't remember if you can grab ledges. I only played it once. Need to play it more.
Flat Zone 2 - Just slightly less crappy than Flat Zone. The new random events that happen take up almost the entire area and just really screw with the game. Not fun and not good for competitive play either.