Saying BRINK is a disappointment is going a bit far, but I will agree that the game I'm playing seems different than the game that was advertised. I'm still enjoying it quite a bit, but I will admit there are some issues that need to be dealt with. Before I post my gripes, I just need to make clear that I've tried the challenges, single player campaigns, and the campaigns while teaming up with a friend; I have not jumped online with a server filled with people, yet.
My gripes (that could be fixed through patching):
1) Teammate AI is abysmal on all fronts. Medics either ignore you or ignore getting shot on their way to you. Oftentimes, classes who are responsible for completing the next objective will stand in front of what must be destroyed/hacked/repaired and do nothing, even when you are not the proper class to complete the objective. Friendly bots also concern themselves more with control consoles rather than the main objectives, and aren't big fans of grouping with humans or protecting them while they attempt to complete a task.
2) Enemy AI is brutal. The above mentioned points would be humorous, even forgiven to a certain degree, if the enemy AI wasn't so elite. They flank, they attack in waves, sometimes have crazy aim, and properly target the most dangerous bot/player on your team. Why can't our team do the same?
3) There should really be a lobby system to play with friends online. I'm not sure how it works on the Xbox 360 or PS3 (well, to be fair, nobody knows how it works on the PS3 yet,

), but here's what you do on the PC: inviting someone is fairly easy. You start up a game, open up your steam menu, click on your friend's name, invite them, and go back to the game. The only major problem with that is having to actually start a game before being able to invite. Getting invited is a bit more annoying. You get the invite, open up your steam menu, click on the invite dialogue, click on "join game" in the server window, enter a password if you need to, close your steam menu, and click on another join button in the game. Not very intuitive...
4) Headshots need to do a heck of a lot more damage than they do. I understand that with upgrades and just the general way the game works, a 1 shot insta-kill may not be ideal, but there is little in the way of body region damage scaling, and I feel that this is a major flaw as it also makes sighting your gun worthless except in the cases of long range firefights, which are very rare given the map designs. Somewhat tied to this is the personal request that sometimes you just die and not get incapped - again, that last bit is a preference, and not an inherent problem.
5) Weapon loadouts are getting reset for some people. I am one of them. I would like to see this fixed.
My gripes (that probably can't be fixed currently, but could be addressed in future DLC):
1) Allow multiple classes to complete given objectives. Now, class specific objectives are a good idea in theory, but the upgrade methods in this game favor specific characters for classes, meaning that a lot of us have one "soldier" character, one "operative" character," etc. Tying in with an above complaint, sometimes your bot buddies are drooling masses of uselessness, and it would be nice if you could either break into a safe by cracking it with an engineer or blowing it up with a soldier. Either that, or give the options like "Hack this terminal to open a security door, or blow it open."
2) Map design that better emphasizes the freedom of movement feature. The map designs in this game are very nice, I just don't feel that the parkour is as important as it was advertised.
That's all I can think of for now, but I like to think that addressing these issues would go a long way towards making this a more solid gaming experience.