{Disclaimer for the Masses, intended to show my background and general position This is NOT an insult, so please don't take it that way.}
Speaking as a Level 58 Warrior, with skills split fairly evenly between the Arms and Defense trees. I'm good at playing my character and role, and so have a full dance card. The people I party with, especially spellcasters, often seek me out for return appearances. This is the standard I use to judge my performance, and not "Own-age" or any lack thereof. The opinions you are about to read are MINE and based on MY experience. Other Warriors with different builds may well have very different views and experiences. I would LOVE to hear any well reasoned posts to the contrary. If you do NOT play a Warrior, or have not played a Warrior to at least 40+, then In My Very Humble Opinion you don't have the background to change my mind on these matters. Any and all reasonably worded responses from any class will be given full weight. But if (for example) you are a Rogue who *thinks* (s)he knows what it's like to be a Warrior.......
{end_disclaimer}
PvP??? Forget being a Warrior. Completely. You absolutely want to be a Paladin if you want to be a Melee fighter in PvP. A GOOD player with an Arms/Fury build can win against half-a$$ed players of all classes. An outstanding Warrior cannot regularly win against good players of most classes, and if you're opponent is as good as you are, then the odds are stacked aginst you. Know this.
But you said no PvP, so that makes the choice easier...
If you want to do a lot of damage and watch your dying enemies fall at your feet??
Forget being a Warrior or a Pally - be a Rogue, Mage, Warlock, or a Hunter. Learn to play them as they were intended and your foes will fall.
If you want to be Survivable - Be a Paladin They have the same armor/weaps and effectively 3X the life. Plus some cool buffs.
If you want to be Versatile, or aren't sure what you want to do and want to try lots of techniques and play styles - Be a Druid or Shaman. You can spellcast some, tank some, and buff/heal yourself and others.
If you want to be in demand for the entire game: Be a Priest. Good healers are always in demand. Always.
If you like getting the snot kicked out of yourself so that others can destroy the enemy, and want to be the one that people turn to for high end instances,
(when there aren't any Paladins available, ayways) - Be a Warrior. (half joking)
If you take it personally if those around you die when you're still standing - Be a Warrior.
If you want to be the one that protects everyone else - Be a Warrior.
I know I'm making it sound like Warriors suck a whole lot more than they really do. They don't "suck". Not at all. But they are underpowered compared to most other classes in the game, and you end up working quests that are slightly below your level to have the same ease that other classes do when working quests at or slightly above their levels. On the positive side, Warriors are the absolute KINGS of controlling Enemy Hatred during battle. When your mage starts throwing Nukes, or the Priest lets loose with some serious healing love, then it is the WARRIOR who can distract the now VERY ANGRY Mobs away from them.
Nobody else in the game does that. And if you learn to do that well, then YOUR dance card will also be VERY full.
In short - Warriors are the best tanks in the game, and are designed to gather attention to themselves and take the beating so that lightly protected damage-dealers can do their jobs. But they aren't big damage dealers and there is a LOT more to being a good warrior than running over to something and whacking away. Paladins are better if you just want to play and not die a lot.
Keletarise