This review said it best when the reviewer states:
"...there is not one original concept, which makes Quake 3 essentially a game you've already played. Beyond that, there are virtually no gameplay tweaks available to add variety to the modes. Every match is very similar. Eventually it all becomes very mundane.
The weapons don't really help. Again, you've seen each one before, and although the balance is very adept so that no one of them will rule the Arena, none of them are terribly impressive or subtle. Quake 3 is not a game of intellect, merely of twitch skills..."
Quake 2, although lambasted by GR for only adding "colored lighting" to the FPS genre, was a far superior game than Quake 3 when you take out the higher end graphics of the latter. Quake 3 was BORING. I bought it at about the same time I bought Unreal Tournament and although I was a die hard Quaker up till that point, Unreal Tournament DOMINATED my gaming time soon after leaving Quake 3 in the dust. Though it's singleplayer wasn't much more than basics, UT's bot assisted assault gameplay was awesome, fun and challenging. Add some map packs from online and it got even better. When I got bored with UT months later, I downloaded UT: Strike Force (similar to Counter Strike) and the fun continued. Graphics were superior in Quake 3, but, gameplay is EVERYTHING. What's funny is that even with the advent of QUAKE: Live where you get Quake 3 gameplay and Quake 3 graphics on just about any modern computer, the game still hasn't gotten any better with the exception of convenience. Quake 4 was considerably better, but, Quake 2 is probably the best of the bunch. Devastating weapons, an interesting singleplayer mode and awesome visuals made it a champion of it's time. Interestingly enough, Unreal was released around the same time Quake 2 hit shelves, and Unreal had a deeper, longer and more varied singleplayer experience.