I've completed the story and quite a few dungeons and it does have some problems.
The story is not engaging at all and gives no real sense of urgency to resolve whatever matter there was (which still isn't clear to me at all).
The AI is awful. Difficulty is from increasing number of enemies and how aggressive they are, but not from improvements in the tactics they use.
Classes lack diversity. The game could use some class specific weapon classes to mix it up a bit. They could have items that give modifiers to your abilities to transform into something unique.
Sub-classes feel mostly the same, but you are forced to level up the skills separately if you want to try something else. I wish they'd just level together and you pick which you want. I don't enjoy grinding out skills.
The loot diversity could use improvement and hopefully can be fleshed out in the future. I feel they should look a bit more at Diablo for some inspiration on how to make items into something more appealing.
Players drop out of dungeon groups leaving you on your own very often. The dungeons do scale down when this happens, but not the experience I want. There needs to be punishment for leaving multiplayer PvE content and the game needs to make an effort to fill out the group once someone leaves.
There needs to be more dungeons. It's very bare right now and most of the dungeons take place in areas you had quests previously.
PvP content is generally fun, but there needs to be some efforts to balance out player skill levels. It feels like you either get on an extremely good or bad team, but never have I been in a balanced match. I feel if they can get the team balance right, then this would improve considerably
The way to gain gear is too much of a grind. I'd prefer just getting a piece of loot for each dungeon I complete with a small chance for more to drop while completing it on higher difficulties
There are some good sides to the game as well:
The gun mechanics are very sound and most weapons feel good to use.
PvE content is fun if you get in a competent group that doesn't bail on you
There is a natural stream that runs under my property that supplies the water. It is always crystal clear and tastes great. I have no problems drinking it from the tap. I had it tested by my state and they said there were no problems with it.