It's all in the traits. They don't mean much early on, but when you start figuring out that they were built very well, I found a lot of enjoyment in the game. It's subtle - in casual PVE you can throw your traits all over and be 'fine' (although less so than just throwing points into a talent tree in WoW. WoW's gotten to the point where you literally can't pick up something that doesn't apply to you) but with a little creativity you can make great builds that are very powerful.
Instead of just 'spamming 1 and 2' you can start to pull many mobs and utilize all of your skills to avoid taking any damage at all (and not by just circle strafing around spamming 1 and 2... why is this even an argument? yes you can do that in any game, and in none of those games is it an efficient or fun use of your time) or use those abilities to benefit your party in some way. Every prof has a way to handle these situations, in their own personal flare.
I could write an essay about the strengths and weaknesses of my necromancer's build & the traits/utilities I swap out depending on the situation, and it would be unique to my profession. The professions have depth for those who want it.
And, as a final note, every prof does have something that they excel at:
(Please realize that I am just outlining the strengths of the professions. Every class can do more than what I list below, but the OP wants to know how they differ) Guardian: Excellent party healers and buffers. Also great at area denial. Everyone wants a good guardian in their group - this is the class you study & learn if you want to be readily accepted into dungeon groups. Thief: Every build has high damage. The best resurrectors. Best Mobility. Initiative makes them play different from every other profession (it feels a lot better than the Energy mechanic) Ranger: Highest ranged projectile damage (lots of projectile finishers) and is the only class that can fully control a pet. (Assuming you keep it on passive, which you should) It appeals to the... 'pokemon gamers'. Gotta catch em all. Pet swapping is a nice mechanic too. Necromancer: Best party condition removal - they don't just remove conditions, they transfer them to enemies or they benefit other necro skills. Extremely high survivability (either as a minion or life steal/deathshroud build). Necros are nearly immortal, even using daggers. Elementalist: The ele is probably the weakest class. They are good at a lot of things but the only thing really unique to them is access to a huge amount of combo fields. Mesmer: The mesmer takes a while to get its momentum, but the people who play them love them because they're very unique. Extremely high durability with the staff, clones & phantasms have so many options if you build for them. Their party skills are adored by players (portals, the aoe quickness, aoe stealth) and their combo fields are very powerful in groups. Engineer: This is basically the good version of the elementalist. Extremely high versatility and most of your options are excellent. Engineers have a tool for every occasion and they aren't limited by the weapon/attunement swap cooldown. Warrior: They have the highest damage potential and they're just straight up beasts while doing it. Best combo finishers (blasts).
I hope this helps you understand what Anet has given you a bit better. GW2 is a great game.
Last edited by Naughts Skyway; 2012-10-21 at 04:54 PM.