I have Lock On: Modern Air Combat. It's the most realistic aerial combat simulator I've ever seen (and I've played a lot), with Aces High II being a close second. Although realism is the feature I look for the most in aerial combat simulators and Lock On has the most of it, I don't enjoy Lock On very much. Why is this? It is because modern jet fighters do most of the work for you. They avoid the stall for you, they calculate your flight path for you, they even aim for you. The skill required to fly a modern fighter jet is great, but it is very small compared with the skill required to fly a World War Two era fighter. Why, a fighter jet can climb to its ceiling in about thirty seconds! And it has no torque or gyroscopic effect.
It is true that all simulators greatly simplify many aspects of flying fighters, but they do so proportionally; while it is indeed harder to fly a real fighter jet than to play Lock On: Modern Air Combat, it is also much harder to fly a real warbird than in Aces High. I speak of engine and fuel management and similar things. Regardless, both in simulators and in real life, modern jets are very easy to fly compared with older warplanes. To put such a talented team as Hitech, which is creating things that no one has ever made before (made well, at least), in charge of a simulator that has already been done well by Eagle Dynamics would be a terrible waste of talent and resources.