Reason 1: Though Brink does not include TDM there is no reason you cant play that way. I would encourage a few of my teammates to do this. They hold the enemies back while the rest of us do objectives. Everyone wins [except the enemy]. I have friends who hate Objective based games, Fine let me do it just ignore your objective wheel. You get TDM and i can pretend your doing it for teamwork and can feel morally satisfied.
Reason 2: Despite the terrible presentation Brink has an awesome story. It provides good reason for fighting for both sides [maybe not emotional weight but we're not here to complain]. Much better than current Evil PMC or evil terrorist plots.
Reason 3: Splash Damage is treating us like humans. Can you Imagine if Games-Workshop or Bethesda had complete control? Bethesda didn't apologize for how bad Fallout: New Vegas was at release let alone offer free DLC. Splash Damage is even making Steam treat us decent. It might just be me but I appreciate the fact we're being treated as people not just walking cash signs, And i believe it goes along way in helping me get over my disappointments with brink. I might never pre-order a game from Bethesda or Splah Damage again but i wont be turned away from the possibility of buying one of their games.