Rock, paper, scissors is a very narrow field of counter balance. The sheer number of weapons, attachments, and abilities in Brink means that no single item is going to have a direct counter, but rather you will be able to put together a guy who can effectively Paper the other guy's Rock (hmm, did that sound dirty?)
Right, But It was just an example I'm sure we could add even more choices within the field of play to add to the complexity (Ex: Red Jaws of Life [Scissors] beats Gray Sheet Metal [Paper]

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, But I doubt it would come anywhere near Brink, what game has? That and....It's a game you literally play with your hands lol
Silent Running is the counter to sound whoring (effectively a buyable advantage these days) and the obsessive need by the mainstream gaming community to depend on radar. You can hear me moving and my footsteps flare my exact position on your radar just incase you aren't listening.
To be Honest I really think Running shouldn't put you on that radar in the first place, But that's my belief. What games would you say depend on radar? Lol go on BLOPS it's so useless because 75% of the lobby is running ghost so it won't change a thing. I Think it's just a factor to put you in the fight faster, Think about it you see someone shoot [un-silenced] or get marked, you now know where they are, and have what choices to engage them in depending on your play-style , instead of running around aimlessly (especially for newer players)
People use perks like Ghost and attachments like the silencer because radar is over powered and they would rather have a sporting game than a constant blood bath. I think, however, you will find that Silent Running will be skipped by the majority of forntliners in favor of more damage or defense and will get used by those that are playing the stealth game.
Stealth is always an alternative to other play styles, But if your not trying to get kills in something in that requires it (Objective
NEEDS defending, Playing TDM [YES I know this game doesn't have TDM, It's just an example]) You probably aren't doing your team a favor. If you aren't using the tools givin to you in the first place, It's not over powered. Now when you have your choice to pick something (Your load out, Your weapon, Your abilities) That is where the game changes drastically. And that is why I don't want to see cookie cutter builds on Brink, I love the variety in the game, and too see MOST people run with Silient Running, would be sad to see. (But hey this is my opinion, Doesn't mean I'm wrong or right)