First off, I think A attacks (smash attacks) would be somewhat similar to Mario but not by much... anyway here's what I think.
B: Hammer Throw
Throws a hammer forward. The hammer is thrown a little slower than Wolf's blaster and doesn't go quite as far, but does more damage.
>B: Fire Drive
A short-range attack. Paper Mario pulls out a flaming hammer and swings it in front of him. Charge by holding B.
^B: Paper Airplane
Turns into a paper airplane and flies upward. Similar to Meta Knight's ^B.
Alternate ^B: Tornado Jump
Three small tornadoes form around Paper Mario, allowing him to jump very high. Length of jump is similar to Mr. Game & Watch's ^B.
vB: Repel Cape
Paper Mario covers himself with a red cape, making him dodgy. Any attack received within a short period of time will be countered with a quick punch. Similar to Lucario's vB.
Alternate vB: Spike Shield
Paper Mario spins around, creating a blue shield of spikes around him that lasts about 1/2 second. Paper Mario is invulnerable during this time. Timing has to be just right, but does about 10% damage and some good knockback.
Final Smash: Showstopper
Mario stands in a defensive position as large stars come in from the background. These stars are larger, about 3 times faster, and do more damage than Andross' plates. There aren't as many, though. Once a star passes through an area, the area becomes a blind spot for about 7 seconds after the Final Smash has ended (nothing can be seen there; just black).
http://www.youtube.com/watch?v=CB_An_p7DO8 (starts at 0:27)
ALTERNATE COSTUMES:
Red: Normal
Green: Wears L Emblem (Paper Luigi)
Blue: Paper Jumpman (blue shirt, red overalls)
Other 1: Wears W Emblem (Paper Wario)
Other 2: Wears L Emblem and W Emblem (Paper Waluigi)
Other 3: Paper Fire Mario (white shirt, red overalls)
TAUNTS:
Taunt 1: Paper Mario looks at the screen, gives a thumbs up, and then adjusts his hat.
Taunt 2: Paper Mario spins around and wags his finger toward the screen.
Taunt 3: Paper Mario jumps back a little while waving his arms in the air, looking surprised and startled.
He would somewhat inherit the Game and Watch feel but not by much.