I think you're ignorantly giving too much props to Brink. [[ Ignorant means not knowing any better; lacking of knowledge of an area. Like politics or something before I get banned again for that word. ]]
Killzone has classes, Battlefield has had classes for many years now. Team Fortress two has more classes then this as well.
I don't think you've ever played CoD either, people take vantage points all the time. But in CoD Players play more for kills then to help out their team, however if you're with a few friends or a good team then you'd see people covering each other.
As for moving around maps, again i'd have to say CoD gives you more options and viable ways to get around a map. There are more routes and side routes in your average CoD map then Brink. While the movement system is more limited, the maps are far more open for ingenious ways to get around. [[ Besides Black Ops which seemed to want to give more of a funnel points kinda thing which doesn't work for quick kill times. ]] In battlefield there's APC's and vehicles to get you around the map, besides the nice old fashioned running through alleys that can stealthily get you around. Plus you can help out your team mates more then in Brink. [[Their system is better. You can give heads up to other plays that you need health or ammo, even spot enemy players and doesn't need a specific class skill. ]]
The weapon customization is alright, but could be better. Variations in colors and different stocks and barrels to change your gun even further, sort of like Army of Two.
I think a lot more has gone into all the Call of Duty's and Battlefields and Killzones due to how much more content they offer then this game. Which is good, but severely lacking.