Frankly, I feel that the increase in visual realism (aka 'eye-candey') just cannot be delayed anymore.
Times change. How people view games change, and the customer base also changes with it. Most of us currently playing AH have seen what the early days of PCs were like. I used to have a great deal of fun playing ascii coded games.. and the RPG that I really loved were the totally text-based Ultima series from Lord British.
To us, AH1 is more than enough. Eye candy is always 'secondary', as long as gameplay is always smooth and fun.
But think about the teenagers now. These young people were born in the late '80s. When these boys and girls were playing games as toddlers, they were using Pentium III based machines with GeForce2 cards and internet connections. In their mid-teens, these people are now playing games with incredible visual qualities. Anything less than they've already experienced, they will be turned off by it.
It's just how things go. The standards of the eras never flows against time.
These people are offered with a variety of other games of different genre(RPGs, MMOGs, action, driving, FPS, RTS etc etc..) that has incredible level of graphics. Would they even care about simulation games, if it at least didn't have some graphical quality that sparks interest?
To the young people, graphics, is a part of game play. If it looks old and outdated, then the game is not fun for them. They're not like us, DMax.
In a few years, these young people will also become potential customers for Aces High. Are we gonna be still saying that "AH looks sucky, but that's okay, since gameplay is what matters the most"?
They are gonna carve that on AH's tombstone, DMax.
AH still has a lot of catching up to do. AH2 is a refinement of AH1 engine(at least I think so), but it's shown tremendous potential, when compared to old AH1.
This should not stop, ever.