They might have made a game that was supremely balanced, at one point--on paper. Then they started making the game, and one compromise at a time, one extra idea added (or scratched) at a time, they undermined it so fundamentally that a few moments of gameplay are all it takes to see how painfully bad it got.
Let me make this as simple as possible. Maybe that will engender even MORE argument, since my point is (at heart) a superlative, but here goes:
The worst part of objective-based online multiplayer games is starting at A, running to B (or worse, past B all the way to C) only to die almost instantly.
Brink, through a combination of design choices, does it's best (inexplicably) to HIGHLIGHT that element and force it in every mission.
Which elements? Sorry, no easy explanation here. It's a combination of weapon damage / player health / regeneration / weapon fire spread / accuracy zoomed / accuracy no-scope, and a dozen other factors. The linear, all-chokepoint levels certainly don't help.
You can't temporarily "hold" or occupy territory in this game the way you can in, say, Bad Company 2 (which has, purely by coincidence, roughly similar weapon accuracies / damage, but level design, squad-spawn and healing mechanics that allow this "occupation"), leaving you to reach your objective and fail as a result of pure inevitability due to the defenders' advantages in spawn distance (and that ALONE is all they need with teams otherwise at parity).
Don't believe me? Be honest: how many online games make it past the first objective? Almost none - the defenders sit and slaughter the attackers. If attackers ever advance, it is because they are overwhelmingly better than the defenders. Parity teams (even a moderate attacker advantage) of real human players will always result in incredibly boring rounds.
In Bad Company 2, a "close" round was an attacker failure on the last set of objectives. In Black Ops, a close game involves a few objectives destroyed. In BRINK, "a few objectives completed" (despite the technical loss) is actually a HUGE win for the attackers.
I'd say, all in all, "Be More Objective" is a perfect storm of everything about the game that's laughably bad: useless AI but mission objectives that NEED more than one coherent attacker. And, to wit, mission objectives that require you to run, run, die, repeat, until you quit and play a better game.
I came here to post this, one single message. If anyone at Splash Damage reads this, please consider these things for your next game, because I know you're moving enough units of this title to develop again. Design your game to MINIMIZE the run-run-run-die-repeat grind of online FPS, not encourage it.