I have to disagree - there is very little that pushes things today and, for the most part, fps play like dumbed down versions of what we had before. I enjoy BF, but movement and aim wise it's massively less demanding than any no. of fps from the mid 90s. Part of the issue is current fps are designed primarily for consoles, with the limitations pads introduce, and then ported to pc. Hence slow movement speed, little verticality in maps and uber quick time to kill as you just can't twitch aim or track well with a pad (I'm a big console fps fan btw. there's no bias here - just the way it is). Now compare this to when fps were being made primarily for the pc, with maps and modifications designed by pc fps fans. From a pure mechanics point of view these games/mods were more interesting to play with skill ceilings that eclipse what we have today. There's a reason players tire of current fps once they've unlocked everything - it's because the core games have little depth to them. Now compare this to something like Quake - you can play for a decade and still be trying to improve your skills.
This isn't a request for every fps to be a super speed, twitch aim, arena pro-fest. But there was a time when games like Counter Strike, RTCW/ET, TFC *insert great pc fps from yesteryear* etc were being released on the PC and rather than building from there, we've taken a big jump backwards. As others have said, dlc and the resulting lack of dev tools is a big part of this. Which brings us to another problem - we're limited to what devs produce, which often isn't great. Especially when it comes to map design. So we're getting fps designed for consoles with maps that aren't that great and no way to improve things