The reason I am attracted to Brink is specifically the fact that it will be a splash damage product and therefore will be created by the best team-based FPS creators. I personally hope to see very similar game play mechanics and level design and hope that the game will not sacrifice these aspects of the game in order to attract more standard FPS players.
There are elements that are similar to their older games, and many of the people who worked on Wolfenstein as well as all of the people who worked on Quake Wars are still part of the SD team. So, it would be easy to think that there's a large risk of Brink becoming more of a sequel than its own game. To me, the gameplay footage dispels any such worry. I say worry because if I wanted to play W:ET or ET:QW, I would just go and play those games.
SD's main goal with Brink seems to be one of creating a new game that is unlike any game out, that includes their own games. Experince in making [good] objective, class, and team based games will lend itself to making Brink a better overall game, but I don't expect or want it to make me think of either game, or any game at all. Yes, both of their other games had successful gameplay mechanics and level designs, but I see no reason that Brink has to be similar to either game in those aspects for it to be successful. I hope Brink will be entirely its own game.
That being said, I would prefer they mimic their own games over current mainstream shooters. But, I don't think being unique when compared to either would be a "sacrifice".