Performance shouldn't be a problem. I'm RECORDING at 1080p, 8xCSAA, everything max, and I'm getting 120fps. I have an i7@4Ghz and 570, but if you can run any of the recent games at 1080p this shouldn't be a problem.
One thing Valve needs to improve on is the level loading. Their approach was better when games took 1 min to load a level, but now its sort of jarring to see load screens so often. I will admit the scale of some of the levels isn't something we see all that much, but they should take some cues from the open world games and stream the data in the background or something. I guess all that stuff is easy when you are not the one who has to do it.