I'm going to roll Paladin to 50 as well, because while Warrior is great at what it does, it suffers against heavy damage. Warrior is currently built to be a trash/add tank, and I have no problem with that, as I played a similar role on my bear druid in WoW. Our platey facerolled the boss and I tore all of the adds to shreds. If I tried to main-tank hard hitting bosses like Tortos, I required a lot of healing and was prone to sudden death syndrome due to a lack of anti-spike tools, but I held aggro much better on multiple mobs and did more than my share in mowing them down.

As soon as people start overgearing the content, WAR will start to become the preferred class even against raid bosses due to their damage output and higher health pool. Right now, though, PLD is the way to go if you want to clear Coil. As easy as it is to level up and gear alternate jobs, I don't see it as a major issue. Suck up your pride and do what's best for your group. You'll get your chances to play WAR.