You're not the only one who feels this way my dude. Campaign is gonna be fun and I'm sure there are gonna be a bunch of ways to approach the objectives but after a while it might get repetitive. I guess it all depends on who you're playing with and how creative you are.
The thing that boggles my mind, is how people will complain about how Brink doesn't have enough game modes, but at the same time, many of the ones complaining, play nothing but DM and TDM all day long. Ultimately, it isn't that the want Brink to offer more gamemodes, it's that they want Brink to to have the gamemode(s) that they enjoy playing - they seem to forget that lots of people enjoy playing the type of gameplay Brink will offer, over and over and over again.