I have a 105 max aa warrior and a 105 nearly max aa paladin. I have a lot more experience playing my warrior. My paladin is my "group B" tank and really all I know about the pali was to set him as a bot. I don't really play him. That said, I know knights have gotten a boost for tanking, but not really sure how that compares to warrior.....although it better still be a distant second since paladin's can out-right heal themselves and SK's can life tap to help mitigate incoming damage. However, I have a couple clerics, a shaman and druid and whatever healer merc to do all the healing.
For grind camp it really doesn't matter too much. For easy grind camps, knights might be better because you might be able to get away with them just healing themselves and add another DPS class. I did an afk camp where I my cleric was invised and I didn't know. Left them overnight afk and the cleric did zero healing because when invised, he does nada. My paladin was able to heal himself and the group the whole time. It was an easy camp, but if the tank was my warrior...it'd have been a complete wipe. Warriors tank the best, but they cannot replenish health bars.
Now for an actual tough encounter, I'd rather have a warrior and a real healer (and maybe even a back-up) since they mitigate the best for incoming damage. Where the knights can help replenish their health bars a warrior just keeps it from going down as easily, which I think works much better for when incoming DPS can spike.
Not to mention Last Stand and Pain-Doesn't-Hurt, which can make a warrior damn near impossible to kill. Last Stand refreshes in 9min, PDH refreshes in 5. Get the baby last stand BP and you got another God-mode disc that refreshes in 5 min. For the really tough shit, you use a combo, but most bad pulls, just pop one and you'll be like 'fuck crowd control lol', just tank em.