Uhh, for a start the world is probably as big as WoW's, if not bigger.
Secondly, the class system isn't JUST about one class like WoW's boring system.
Lets have a look, so you have :
Warrior - Close up
Ranger - Distance
Elementalist - Straight out Mage
Monk - Straight out Priest
Mesmer - Anti-caster, attack prevention and disruption
Necromancer - Curses, HP degen and drain, undead raising
So over half the classes are casters? WHOOP DE DOO, you can combine them in ANY damn way you want.
I have a Necro/Warrior who is very much battle focused, so the primary class is Necromancer? Doesn't mean I have to cast, they have enough skills to use in a purely battle sense.
So do Mesmers, so do Monks, so do freaking Elementalists.
You can combine them in any way you want and they will WORK, there is no godly invincible, balance destroying job that beats everything else, nor will amazing armour and fantastic weapons make you better than anyone else since skill is required.
WoW is about grind, about item-whoring and hunting and wasting your time in the same places levelling and hunting items just to be able to get to the next area where you can grind and hunt items, and so on.
In GW, I've never had to grind for items or levels, all I've gained is in the process of playing the game and doing quests, all the items I use I've crafted myself from items I found while progressing in the game, or items I've bought from other players.
GW is just basically a hell of a lot more friendly than WoW.
I have had FUN, I do not find grind fun and honestly, I don't see how anyone (aside from Koreans, all they do is MMORPG) could find grinding fun.
And tell me you at least played beyond the searing, since I HATE when people make decisions on a game when they've barely even played past the newbie area.