I've recently been doing some high altitude flights in the F18 and i've been noticing how bare and un-natural the sky at 30kfeet + looks. The top edge of the haze in the distance is very sharp and it doesn't fade nicely into the sky colour. Also even at 60k or 80k feet the sky seems to be all one colour rather than a nice fade to almost black directly above you. Also I noticed a lack of stars when you get up to that height.
One of the other sims that I play a lot is DCS which is clearly a different kind of sim, but it does do the high altitude sky very well. So over my lunch break today I decided that I would take some screenshots in both AFFS2 and DCS1.5 from the same heights and then photoshop the DCS sky into AFFS to show you how different it looks. I think you can agree that it certainly makes the rest of the graphics in AFFS2 really pop once the sky is more dynamic.
--- Rick click and hit "open image in tab" to see the full size images ---
Remember this post is not "AFFS2 Sucks! DCS is so much better!" I'm simply saying that down the line I would love to see the sky look somewhat like this up at altitude.
Here is a video of the sky in DCS to show you as well if you aren't familiar = https://youtu.be/01linz-wtSM?t=1m51s
Also here are a couple of IRL shots from high altitude.