Arlo, compared to Il2 the graphics are quite bad in AH, this is most noticed when it comes to effects such as sun, sky, smoke, fire, hit sprites. Muzzle flashes are way over-done though.
Don't just look at the plane detail, which are better too but look at all small details, cockpit shaking, engine mannagement, different boost options (water methanol, over boost etc), clouds, rain, snow, thunder, haze, fog, thermals etc etc etc, it's the small details that make a game feel more realistic, AH is nowhere close to the "feel" you get in IL2.
And if the extra yet uneccessary eyecandy drags down systems that two years ago were considered fairly decent (in some cases "top of the line") without really adding more than some "ooohs and aaahs" the first dozen or so times they're seen (after which they are as taken for granted as the fuzzy portrayals of the pixels that preceeded them) then it's really a waste of HTCs valuable yet limited resources at the possible cost of a chunk of the customer base that was more than satisfied with the current product.
Such is life in the computer market, if you wanna stay with it you'll have to upgrade sooner or later, 2 years in the computer market is like light years when it comes to most other things, it advances SO quick, you can't expect a company to stay old and have the same system requirements for their game as they did in 1999 or 2001 (which were about the same system req for AH).
Eyecandy is a BIG part of the realism in a game, even more so when it comes to flight games or sims.