Warhammer is a solid game. They didn't over cheese anyone class. In fact they balanced everything out quite nicely. About the only tweak they need at the moment is something to bring the Witch Elves down to the level of their counter, the Witch Hunter. Or bring the Witch Hunter up to the Witch Elves.
It's also nice in that there's only four classes per race, but in WoW, if you play a Warrior, it really doesn't matter what race you play as, its the same play style, with a few subtle differences because of race. In Warhammer, if you were to play a Dwarf Ironbreaker, and then a Elvish Swordmaster, you're really playing two different classes, even though they are both "Tank" Archetypes. The Ironbreaker is a pure Tank, the more he gets hit, the harder he hits back. Where as the Swordmaster would rather not get hit, having a higher dodge and parry rating, because for the Swordmaster to do his damage, he has to dance, getting hit disrupts that dance. Each race has the four archetypes (or will once the next patch comes out). Tank, Melee DPS (Dwarf and Greenskin gets theirs with the next patch), Ranged DPS, and Healer. Each race plays there's differently, and your specific classes counter isn't necessarily in the opposite racial pairing.
The wonderful thing about PvP. Is that it's built into the game, and you can start at level 1. Enter a Battleground and you get your stats bolstered to level 8, 18, 28, or 38, depending on the tier you're playing in. Tier 1 goes from 1-11, Tier 2 goes from 10-21, Tier 3 goes from 20-31, while Tier 4 is 30-40. Enter an Open PvP area and your stats are bolstered as well. You don't have your skills that you would get if you were actually at that level, but your hit points, current skills, and other abilities, all act like you are at that bolstered level. Kill a player, and you gain renown points, in addition to XP. No twinks. Eventually you will level out of the tier you are in, and if you come back, your hit points are dropped to 10%, and you lose all of your abilities, 'chicken'.