My opinion:
Neutrals:
Battlefield (Platforms are fine etc...)
Yoshi's Island (Nothing wrong with it)
Smashville (The most neutral stage in the game)
Counterpicks:
Final Destination (glitchy edges and a weird design that hurts recovery)
Lylat Cruise (tilting, odd design and distracting background, could maybe be argued for neutral)
Delfino Plaza (tons of design changing, walk offs, close to ban)
Luigi's Mansion (hard to kill people, stage changing and other such things)
Corneria - Melee (there are lasers but it's mostly okay)
Green Greens - Melee (wind and stuff, it barely makes the counterpick)
Banned:
Mushroomy Kingdom (scrolling, 1-2 is awful)
Mario Circuit (go cart hazards, walk offs)
Rumble Falls (scrolling and those spike hazards and stuff)
Bridge of Eldin (hazards, stage breaking, projectile spam and stalling)
Pirate Ship (tons of hazards including bombs, catapult, storm, low gravity, rock and everything)
Norfair (the lava hazards)
Frigate Orpheon (the flipping is awful and one side of the stage has no edge)
Halberd (walk offs at the beginning, opprunity for death at the beginning, terrible hazards later on)
Castle Siege (constantly changing, walk offs)
Pokemon Stadium 2 (constantly changing, some of the forms have terrible hazards)
Spear Pillar (the worst hazards ever, BANNED BANNED BANNED)
Port Town Aero Dive (Those cars, weird design where you can't get KO'd from the bottom)
Skyworld (Easy to spike through clouds, no tether recoveries, trying to get back to stage and the platforms respawn...)
WarioWare, Inc. (Do I even need to say?)
Distant Planet (Those items, the rain, the bulborb, walk offs)
New Pork City (TOO BIG, ultimate chimera)
Summit (Low gravity, no edges on the bottom, low gravity, the fish)
75m (horrible design, tons of hazards, walk offs at parts)
Mario Bros. (horrible design, totally wrecks the basic gameplay, tons of hazards, walk offs)
Flat Zone 2 (so many freaking hazards, some of which kill at very low %, walk offs)
PictoChat (very unpredictable, many hazards)
Hanenbow (terrible design and bad for tether recoveries)
Shadow Moses Island (walk offs, those walls)
Green Hill Zone (hazards, bad design, walk offs)
Pokemon Stadium - Melee (transformations that are terrible, bad edges)
Rainbow Cruise - Melee (constantly moving, full of hazards, very anti-smash bros gameplay)
Temple - Melee (TOO BIG)
Yoshi's Island - Melee (walk offs, lousy pit in the middle)
Onett - Melee (walk offs, car hazards)
Big Blue - Melee (Do I even need to say?)
Jungle Japes - Melee (water, klaptraps...)
Brinstar - Melee (Acid, destructible stage)
There, very fair and I think you'll all agree.