What are the best grinding spots for a warrior?

None. Don't grind your way to 60, you'll be expected to tank in endgame instances, and if you can't do that, you won't make many friends. And if you don't do instances, you can't learn.

Oh, and quests are fun anyway. If you grind your way from 1 to 60, you'll miss most of the game's content, the developers put really much work into making the quests enjoyable, and the stories behind them interesting. If you just grind, you have a rather dull game experience, and a game should be about fun, no?

If you still want to grind, or just want to grind to make some money, go find yourself some Ogres. They have nice caves (where you can mine, too), they drop cloth for your bandages, and they're all over the place. Nice and squishy, you'll just slice through them.

I have to add that this is my own point of view, and some warriors might disagree here.