Saddled with a few small flaws and one huge one, this has aged horrendously.
The game looks great. Wrestling games are greatly underappreciated for their character models and the Cube really delivered on this one (though has been far surpassed since, of course). Sound is good, things look right, etc. No problems here, however its the music that is an issue. This game included the nWo and yet lacked the music, using some horrendous choice instead. Many other themes were replaced, detracting even more. Its a simple thing, yet so important.
Also problematic was the movesets, in that most everyone had the same ones. There really wasn't anything unique about anyone else aside from how they looked. Add in the lack of a story mode and you had a game that may as well been on the Super Nintendo: exhibition matches with everyone doing mostly the same things.
This was after years of SmackDown! games going above and beyond with story, moves, etc. and really showed that there was potential on the Gamecube, but it wouldn't be seen within the first game.. Skip it.