3 stock. I'd only suggest 4 in the instance of items (faster pace since everyone has a kill move and to help with accuracy of results)
Neutral Stages:
Battlefield
Final Destination
Pokemon Stadium
Delfino Plaza
Frigate Orpheon
Lylat Cruise
Smashville
Brawl Yoshi's Island
Counterpicks:
Luigi's Mansion - Nuetral
Mario Circuit
Norfair
Halberd - Nuetral
Bridge of Eldin - Banned
Pokemon Stadium 2
Castle Siege - Nuetral
Distant Planet
Skyworld
Pictochat
Hanenbow
Green Hill Zone
Onett
Corneria
Rainbow Cruise
Green Greens
Brinstar
Banned Stages:
Mushroomy Kingdom Counterpick (1-1)
Rumble Falls
Pirate Ship
Spear Pillar
Shadow Moses Island
Port Town Aero Dive
Wariorware, Inc.
New Pork City
Summit
75m
Mario Bros.
Flat Zone 2
Temple
Melee Yoshi's Island
Jungle Japes
Big Blue
Keep in mind that my suggestions are more lax and less ban-happy because, well, it's a new game.
Luigi's Mansion - Neutral
Honestly, this stage isn't so bad. It definitely fits in well as a counter pick level, and the main problems the stage has (camping inside the house, mini cave of life) can actually be beaten by simply destroying the house. The camper can't attack you with projectiles because they'll get blocked the pillars.
Halberd - Neutral
The only problem I'm really seeing is that the Claw that stalks Player A and then attacks Player A, B, C, or D. Cort tells me there's some 2nd claw that I've yet to meet, but from what I can tell, the stage's hazards are telegraphed well ahead of time. In fact, I have a hunch that the stalking claw attacks the lead player, I'm not sure, but I'll need to test more. I also think, if this is true, that it stalks the lead player, and then if the lead changes by the time it attacks, it attacks the new leader, which gives it an illusion of randomness. That'll require some testing.
Bridge of Eldin - Banned
The stage is a walk-off, just asking for Dedede chain grabbing, and then the center blows up, and it becomes an incredible camp-fest. Falco (lasers that travel), Pit (arrows), and Dedede (chaingrabbing) seem to be the only usable characters here. I could be wrong, though.
Castle Siege - Neutral
This stage is really good. The only bad thing I'm seeing with the level is the walk-off part in Level 2 and the transitions, but since they're only temporary, it's not that bad enough to be a major con.
Mushroomy Kingdom Counterpick (1-1)
Before I discuss 1-1, 1-2 is a terrible stage. It's fun. It's not a good competitive stage, though. I suggest that if 1-1 is allowed for counter pick, and 1-2 comes up when someone counter picks Mushroomy Kingdom, simply restart the match until you get 1-1. Now, onto 1-1 itself. There aren't too many problems with this stage, aside from when the stage occasionally has walk-off spots perfect for Dedede to CG on, but they're, again, temporary. Much more than Castle Siege, in fact. I'm a little worried about Jab/Shine/Etc infinites against walls to trap your opponent against a wall until they get KO'd by a scroll, but the last time I saw someone do that, they lost a stock too. If it comes down to 1 stock, and the infiniter wins, as far as I see it, it's just like Bowserciding. The ability to keep your stock after infiniting though is another thing I need to test.
New avatar/location/title
Good **** Papito.
EDIT
And just the fact that I did have to look it up and didn't know what SF2T meant right away kinda proves that nobody really cares anymore.
I forgot to mention in my earlier post quoting you, this is physically painful to read.