Though fighting games are definitely not my thing I suspect this will probably be one of the most successful games of 2007 limited only by the install base. Pretty much 100% of every kid that owns a Wii will want it and I'm sure the vast majority of even casual gamers (senior citizen bowlers excluded) will be interested as well.
I hate trolls.

Systems I currently own: 360, PS3, Wii, DS Lite (2)
Systems I've owned: PS2, PS1, Dreamcast, Saturn, 3DO, Genesis, Gamecube, N64, SNES, NES, GBA, GB, C64, Amiga, Atari 2600 and 5200, Sega Game Gear, Vectrex, Intellivision, Pong. Yes, Pong.