Just my 2 cents.
The problem with TERA is that they lock the class you choose into a role. If your a lancer your a tank, if your a warrior your DPS, etc. etc. You don't exactly get to choose a specific fighting class than you like and then set the roles yourself. You have to play as a tank or dps or a healer or whatever.
There just isn't that much class depth to the game which in some aspects sucks because it makes everything cookie cutter. What double sucks is when you may dislike a certain class but to play a certain role you HAVE to choose that class.
It just seems very limiting although I like most of the classes I can understand a lot of the arguments and troubles with matching dungeon groups and grouping behavior trying to fit together the perfect team. What I didn't expect about Tera was it to be a "new" game but with "old" problems. With the current class roster it would be nice to set roles for them. So if you wanted to tank you could choose tanking skills if you wanted to DPS you can choose DPS skills or if you're really on your game you can mix and match. That would be a lot of fun.