if they are mace spec with the stunning mace (god i cant remember the name now) it can be annoying. basically getting rooted/stunned = death. evasion works now, but in WotLK you'll see some overpower builds that can ***** you up hardcore.
so what do you do?
resilience is huge against warriors, they are built around high crit rates, (30-35 % or more for the better geared ones), so you need to reduce that as much as possible.
After that, you need to keep moving fast and hardcore. always keep them crippled with shiv, thats vital. you want to fluster them with stuns and the like, and you want to use a mouse to move to spin around and try to keep behind them. you dont want to trigger parry on a 2h warrior, and behind them they cant overpower you. fortunately their 'stun resistance' is being changed to 'stun reduction'. this sucks for us for not being able to lock them as long, but at least our stuns are guaranteed to go off more frequently. missing a stun can be fatal.
in a 1 on 1 you want to dot them. w/out outside healing you want to stun, gradual dps, deadly poison (since you wont need wound in this case), and wear them down while trying to avoid getting bled. remember that you can vanish while bled and if you can time the ticks well, you can get a quick CS off in the middle.
like all fights, if you can force them to trinket it buys you a lot of breathing room. you can blind, bandage, stealth -> sap, stealth again, and restart the fight with all your diminishing returns reset.
gear is important against a warrior, weapons are very important, and skill fills in the rest.