I think you just have a lot more choice now than you used to... That's why you see such few "big titles". I mean, consider FEAR MP... FEAR MP is a blast, seriously, it is really fun. However, in a sea of BF2, BF2142, Q4 MP, HL2 MP, CSS, people still playing Q3, plus the steep hardware requirements of FEAR, it just isn't ever going to be as huge as CS. Had FEAR come out with the exact same MP (and contemporary graphics) come out in like 1999, it would have been huge also
As far as future FPSes go, I'm really hoping that Huxely can pull off the MMOFPS well, since it just seems like a really cool combination. Mix the idea of single player and multi-player into a single game, and give people the chance to level up and form clans within the game - awesome. MP with more than just the goal of killing each other.
Too bad, but I think that after a mulittude of delays, STALKER is going to be a letdown (both graphically and gameplay wise). My guess is that they had to bring something (anything) to market after all this time, and most of the original ideas of the game were either sacked or just turned out to not be realistically doable. Hopefully, I'm wrong.