Guild Wars 2 is not quite an MMO, there is no monthly fee and you don't exactly go around questing for people with exclamation marks over their heads, but it is still a fully-featured, deep and complex online experience where you can explore an insteresting world and feel like there's always something else to do while progressing with crafting, building your character and finding loot.
No race but class race
I love the races and classes in Guild Wars 2, they feel like a bit of fresh air after all the MMOs I've played, where in WoW or SWTOR you find two factions warring over whatever the plot tells them to feud about, the five races of GW2 are cooperating in a shaky alliance against dragons and dangers that cast a shadow of menace over their worlds. The races are mostly there to setup your starting zone and some backstory for your character that will bring you out there, exploring the world.
The classes are diverse, interesting and use different mechanics. Thieves can steal abilities from their enemies to use them against other foes and they have Initiative that is used to power their abilities, which aren't on a cooldown like the other classes, Elementalists have a wide array of spells for each elements, Guardians can block often and use shield-based abilities, Mesmer use illusions and clones and conditions (status ailments), Engineers use turrets and kits that completly change your skill set, Necromancers summon creatures and turn into death entities, the list goes on.
This is interesting, because each class feels different than the others and each race has a different feel to its starting zone and primary quest lines.
Where the class system falls short
Your class defines what kind of weapons you can use in Guild Wars 2 and the weapon(s) you equip define the skillset you have. If you are a defender with a mace and a shield, you have 3 mace skills and 2 shield skills. If you have a sword and a focus, you have 3 sword skills and 2 focus skills, if you wield a two handed weapon, you'll have 5 skills from that weapon. Each weapon has a 'theme' associated to it, maybe if you equip a sword and shield you'll be able to fill the tank role or the DPS role, equiping a scepter would make you a healer, et cetera. In that fashion, most classes can do everything.
You also start with only the first weapon skill unlocked and you unlock the next ones by using the ones you already have. This is part of the problem with the classes in Guild Wars 2 and it's twofold.
First, you gain these new skills extremely quickly, you'll be able to unlock all of them by the time you reach level 3 and if you have a weapon of each type on hand you'll see everything there is by level 5.
Second of all, it's everything there is, attack-wise. You won't gain special dagger attacks at level 30 if you're a thief, nor a new bow skill will unlock in the late game, you have five skills per weapon, and that's that. If you plan on using daggers until the end of the game, if you only find good daggers, if you have passive skills - more on that later - that affect daggers, I hope you like stabbing dudes, jumping on dudes, spinning over dudes, throwing a dagger and being stealthy, because you're going to do a lot of that over the game.
How I would fix that
My idea would be to give less choices of weapons to each classes and take these skills and add them to the list of skills for another weapon, then make it so it takes a little longer to get to more advanced skills. Maybe change how the passive abilities work so they upgrade your basic skills? That could be interesting and keep them being better and better over the course of the game. That way you still learn your skills over time, but you have more than five and they don't look and act the same way through the game.
Character customization
Starting at level 5 you begin earning skill points. You can also get more skill points by doing skill challenges scattered thorough the world. These skill points can be spent on slot skills. You start with a basic healing skill that can be changed and the three other slots are locked until you get to certain levels. These skills range from passive abilities to summon spells to additional non-weapon specific attacks.
They are a nice addition but are trickled down slowly and you won't know what to unlock when you get your first points because the effects are so diverse. You might want to get a passive precision buff or a poison that affects your 3 next attacks every minute. Not to say that these slot skills are a bad idea but it's unclear what you should or shouldn't take.
At level 11 you start getting traits and they give you passive stat bonuses and special passive effects every five levels. They are split into five branches of which you can max two if you play the whole thing and some effects are more useful than others. That's perfeclty fine as long as you know what kind of character you want to play. You will get abilities like "5% chance to gain Might whenever you kill an enemy (60 seconds cooldown)" or "Your minions have 20% more health". That kind of stuff.
This game is too hard
Guild Wars 2 is what World of Warcraft used to be in some sense - too hard. I remember not so fondly a period of time where I had to stop between each encounter and eat/drink to get my HP/Mana back to appropriate levels for the next fight. I remember when dungeons were about pulling exactly as low number of enemies as possible. Nowadays WoW is way more casual, you can fight forever and I've ran dungeons in such a nonchalent manner that the challenge isn't there anymore.
Guild Wars 2 is not really casual. Fighting multiple enemies at once will result in my death, fighting enemies too quickly one after another will result in my death, trying to tackle event bosses resulted to my death. That last part makes sense because these bosses are supposed to be fought with groups but when I want to gain Skill points, I should be able to fight the boss alone. And more often than not, you don't know what you did wrong.
When you fall to your death, you get into a little 'Fight to survive' minigame in which you have to kill an enemy to get back up. Even if you do, your equipment becomes damaged, you lose maximum HP for a while and your HP when revived is ridiculously low so you might just fall over instantly until you get sent back to a waypoint. All characters in Guild Wars 2 can revive others so if you're playing with a party it might make things easier.
Another thing that increases difficulty is the fact that your level is always scaled down to the area you're in. So no matter how strong you are, if you go to a level 3 area, you'll be level 3 and the tough monsters will still be tough. It adds challenge, I'm sure, but it also makes grinding to be able to beat tough encounter more or less impossible.
How to fix this
Easy, make the game a bit easier! It's not enjoyable to have three or four enemies respawn at the same spot and kill you without you having the chance to do anything. Maybe removing the level scaling? I'm not sure if I like the idea of adding challenge by removing your stats whenever you're in a place that should be too easy for you.
The crafting system is full of good ideas, but...
In Guild Wars 2, your inventory is mostly never full of crafting materials of all kinds like in some other games because you can send at any time all materials you have directly to your 'collection' which is infinite space to store these kind of items. Then when you are at a crafting station, you can use these items from your collection directly into crafting. The best thing is that this is cross-characters so you can use your materials with all your professions.
To be more down to basics, professions range from Artificer, Armorsmith, Cook, Leatherworker, Tailor and the like. You gain both profession experience and actual exp when you craft things and you start with a few handful of receipes. You begin by being able to make simple items and you discover more things by combining what you can do. It's simple really, you mix a boot part with a boot sole with a magic item that gives precision and you'll get boots of precisions.
The system works fairly well and is full of little things to make it feel easy to use without breaking the pace too much. Barring the fact that the items you use to gather materials - metals, wood and food - have durabilities that go down and break after a while.
That being said, I've encountered a small issue with the way receipes work, and it's in the fact that you'll get basic materials - copper ore, greenwood trees and the like - in the first area of the game and even if you mine everything you find, you might not be able to move on to the next rank of materials by the time you're leaving that area, and there are no more of these materials in the next maps. So you need to go back in that first area and gather these ressources until you have enough, and that might not be the funniest thing ever. It's also kind of frustrating to mix and match what you have and get 'this receipe needs a level 400 in that profession', because if you can have the materials that early, why can't you use them?
How I would fix it
Easy, add some overlap in the ressources so you get some in the more advanced maps but with less frequency, that would solve this.
So many things to do, some of them funnier than others
There is tons to do in guild wars 2! You can explore the whole map and find all the waypoints, all the 'places' of that map, do all the quests at the various quest hubs, do all skill challenges and find all the vistas (high vintage points that give you a nice cutscene showing the area around you), also there are tons of achievements, you can create your own guild and do world versus world PvP.
The quest system is interesting, you arrive into zones and then you do things from a list and a gauge fills up, when it's full because you have done enough of the thing, you complete the quest and get gold by mail. It's very streamlined. If you don't feel like fighting, you can just gather things or talk to NPCs or whatever else the quests ask you to do.
When I started playing Guild Wars 2, I tried to get everything in all the maps, because I'm a completitionist and because finding everything gives you nice items and rewards. I hit the same wall on my two first characters - finding all the vistas, areas and waypoints in the main capital cities is super boring because you have no reason to go wander around in these huge multi-level maps. And you can't do anything else while you just look around for these very specific areas. It's kinda boring, it might take up to an hour if you're not very thorough, and after a while you'd just wish you could move on.
Another thing that I dislike are jumping puzzles, I'm not sure if any of you have played Maple Story, but the jumping puzzles in there are terrible. Guild Wars 2 tries to add some of them - to find vistas or specific areas - and the 3d controls don't really lend themselves well to jumping on tiny platforms and falling over, having to restart again. It's not fun and MMO controls don't lend themselves well to that kind of action.
Bottomline there are tons of things to do in guild wars 2, but not everything can be a winner. Some of this stuff is pretty hit-or-miss, maybe you'll enjoy jumping around and finding all of the little things hidden in the world.
How I would fix this
Hard to say, MMO mini-games are not always great - like the races in DCUO - but the whole map overloading issue could be solved by not having these things in cities. You have to walk around fields to fight monsters and do quest, but cities never require it.