Halo 2 is not a game of skill, well maybe it is but it's not the same skills you require to play a PC game. Rather than practicing recoil patterns for hours and learning every point to a map so that you can navigate it while flashed you just have to practice sniping, smashing your B button in and shooting the dude directly in front of you. Since you can't actually turn fast enough to get the guy behind you and the sound is nowhere near good enough to work out when someone is coming up behind you you'll never be able to get them except for one hell of a reflex shot or maybe a lucky jump. You may say 'but Halo 2 has a motion detection just for that purpose' but alas, a lot of people don't know how to play Halo 2 and turn that off even on Deathmatch or CTF gametypes. Oh and learning how to stick people with plasma grenades doesn't hurt either.
To create a successful clan you really only need 3 people in Halo 2. Those peopl are:
1. The Sniper - Basically the clan guard him until they get to the sniper rifle and he picks it up and goes and camps it up in some place that you have to execute several jumps to get up to so he can just snipe away to his hearts content.
2. The Camper n00b - This guy just grabs any gun and camps it up, usually near the sniper to pickoff anyone that gets close enough to kill him. His weapons of choice are the Battlerifle, Rocket Launcher or Shotgun.
3. The Whore - This guy just runs around the map whoring people with the Battle Rifle, Shotgun and if he can get it The Sword. This guy just has to learn one skill: reflex shots. The key to winning a battle on Halo 2 is to either have one of the uber n00b guns (Shotgun, Sniper, Sword, Rocket Launcher) or be the person to start shooting first. Just aim sort of near them and the game will automatically lock on and keep them in the middle of your crosshair. You have to turn a bit but there's nothing they can do unless they use the "Hammer The B Button" "skill" to kill you instantly or stick you with a plasma grenade.
Because clans are made of such lame positions Halo 2 isn't a good game for clan gaming therefore making itself fail as a competitive game. Halo 2 is pretty good for chillout gaming with mates though as you just grab a gun and run at em firing madly :D Gotta love how guns have no recoil and no accuracy loss for being in the air.
If Bungie doesn't address the issues with Halo 2 before releasing it on PC it's never going to take off. PC gamers aren't used to a game like this which is why Halo PC failed and Halo CE tried to salvage the broken wreck but also failed. The future aint looking too good for poor ol' Halo...