Holy crap- I just had a massive de ja vu. I remembered reading Moowatcher's oddly quoted post, then reading PIAC's post, remembering all this, then deciding I should tell you all. O_O I SWEAR to god I've seen all this. I know my post is going to get deleted, too- crazy.
Or maybe I can change that by saying something on topic.
If you guys have read IGN head-to-head-to-head-to-head comparison, you'll see the GCN version of the game kinda got the short end of the stick. Besides the XBox version, it's the best graphically, but many things were changed in the PS2/GCN port that Fran and co. weren't too happy about, namely it being a lot easier (They specifically mentioned one very difficult mission in the XBox version where you have to sneak into a CIA building- in the PS2/GCN port, they just give you a fake IS). They also said the Gamecube version got some pretty piss poor extras- the sticky grenades aren't cool and the GBA link up sucks (while the PS2 version got a whole new level). In that article, they said the best version was the XBox one, 2nd was the PS2, and 3rd was the Gamecube (the PC version came in last because it had no extras whatsoever).