I don't want to rant, but this issue is far more important than it looks at first glance. Low FPS not only degrades visual experience, - it degrades gameplay itself. With inconsitent/low FPS player barely controls aircraft, since his muscle memory goes way out of sync with the game. For i.e. - it is a huge pleasure to rip tanks with GAU-8 when FPS is good (i.e. - empty map with 5 stationary units), but it becomes a complete pain when your FPS is low, or worse - jumps from 40 to 10 in the middle of the dive. This experience interpolates pretty much on every activity in DCS and it becomes painful just to play this game.
We can dream of any aircraft in the world to be introduced into DCS, but if FPS issues will be resolved - it can prolong joy from existing aircraft almost indefinitely. This is a #1 issue for me. Dynamic campaigns, F/A-18 and Nevada - all of this is pointless with low FPS, - it would be just as painful to play as already existing stuff.