For anyone rolling a new warrior or contemplating a race change for their current one, racials are an important factor. While they don't matter as much as player skill or gear, they can make an appreciable difference for those looking to min/max. We'll discuss the benefits each race brings to the table.
The first race is of course Human. Their on-use racial, Every Man for Himself, is pretty good for Tanks, although it is situational. Where it really shines is PvP, where it is probably the best racial in the game. Their extra expertise with maces and swords is handy across the board, adding DPS with the relevant weapons. Perception is handy against stealthers in PvP, but don't expect to beat stealthers at their own game too often.
Drarves remain a popular warrior race, and for good reason. Stoneform shines in both PvP and tanking roles, adding survivability and removing a variety of nasty effects. Dwarves also get a noticeable damage bonus when wielding maces; they bonus expertise is even greater than a Human's. Finally, their Frost Resistance can help in WotLK's frost-heavy PvE encounters and against frost-wielding PvP foes such as mages.
Gnomes are our next race to consider. They lack any damage improving racials, and while Escape Artist isn't a bad racials, it is weaker than similar racials. I don't recommend gnome for your warrior if you care about racials at all.
Night Elves are like gnomes in that they lack any damage improving talents, but unlike gnomes they have other decent racials. Elusiveness is a fantastic racial for PvP and Tanking, and Shadowmeld is great for getting the jump on enemies in PvP.
Draenei is our last race. Heroic Presence is a great racial for pretty much any purpose, thanks to the benefit it provides to both the Warrior and his party, although it doesn't stack. Gift of the Naaru is another decent all-around racial; the ability to heal yourself in an emergency can be great for any warrior, although it is most useful in PvP. Finally, Shadow Resistance is nice against Warlocks and Priests.
So what does all of this mean? Well, for DPS your best choice is Draenei. That extra 1% hit is the best DPS gain of the options, AND benefits your party as well. For Tanking, Night Elf's extra avoidance puts it at the top of the list. And for PvP, Human is pretty much unmatched thanks to Every Man for Himself.
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