Definitely the VC. In FS9, I would only fly the 2D panel, because most of the VCs were unreadable., and it really annoyed me when vital switches and displays were hidden behind an unshiftable yoke. Of course, in FSX, I've mainly flown "stick" types -- the gorgeous RealAir SF260, and Rick Piper's new Chippie. So I may yet cuss at that bl*&%y yoke!
All the visual effects stuff -- light bloom, funky water (still looks unrealistic IMO without bow waves...) etc are a "one step forward, two steps back" deal, that stops the sim from being flyable, and makes it into a screenshow generator. Fine if you pause for a screenie, but then switch it off to fly the plane!
Actually, one thing I really
DO like that's not in your list, is the ability to reconfigure, add and remove scenery without having to restart the sim