I gave up tanking on my warrior. I've been a MT since we first started MC way back in the day. After TBC I leveled a Paladin and a Druid. It's crazy how forgiving tanking as those classes are in comparison to the warrior.

Warriors just don't scale well in comparison to the damage that other classes do. Add to that the whole... better gear = less rage fubar mechanic and you have a broken tanking class.

Druids have rage in bear form, but the damage they do is MUCH higher than a warrior so rage from taking damage isn't as big an issue.

http://www.wowwiki.com/Threat

There need to be more % based threat that will scale associated with stats for warriors rather than static numbers.