IL-2 view system is good. Frankly, the now-standard "SNAP"-style view changes are almost entirely the same in quality in every game that uses this method.
However, as some philosopher mentioned, "God's in the details". A small modification makes such a great impact, typically concerning the views, in the air combat sim genre. A half-inch "bar" represented on the monitor that conceals the enemy plane for only half a second is enough to make you completely lose your track of the enemy, and the fact that there is no way around it becomes the single largest problem in an otherwise superb game that is likely to influence other games for a generation.
The customizable head positions, while too lenient in the older planes, is a very reasonable choice, an innovative small idea which people rate so highly of AH! The recently modelled planes have a very reasonable 6-view limit.
Another thing is the "snap" speed in IL-2 is so damned slow. I would understand if it had something to do with the G-forces, and differs upon different conditions, but however, in every given situation the snap is so undesirably slow that frustration builds for people used to AH.
If AH would have a view system that would not allow a transition from 5->6->7 O'clock views(there's an old thread concerning this idea which I've suggested on two programmable 6 views), and would implement some neat-o features such as seen in IL-2, it would be absolutely perfect!
......
Another problem:
IL-2 cockpits are pictoresque, with photo-realistic levels of detail, which is very good. However, there might be a problem with this.
Generally, there is a possibility that a 3D perspective from the actual cockpit, and a 3D perspective represented in a separate way by 2D methods, might actually differ in perspective.
What I mean by this is the cockpits in AH are actual views from inside of the cockpit that is modelled within the plane. To put it simply, AH builds a 3D model with cockpits intact, and then they put a "video cam" on the seat of the cockpit.
However, IL-2 uses cockpits that are modelled separately from the plane. I have reason to believe that the perspective of the cockpits in IL-2 is modelled from photo data taken at the pilot's seat. In other words, they build a 3D model for the plane, then, they take pictures from the pilot's seat, and then, they build a "panoramic-3D" view around the lens of a video cam based on the pictures they got.
So, in effect, AH perspective goes from 3D to 2D(monitor), while IL-2 goes 3D(actual cockpit)->2D(photo data)->3D build based on 2D(cockpit modelling process) and then again to 2D(representation on monitor). This might tend to warp the views a bit, compared to what AH offers.
The two examples are the cockpits of the Fw190 and Yak series in IL-2. These two planes both offered excellent visibility in real-life, and yet in IL-2 they are severely limited even in forward visibility(!), due to problems of the "3D" built cockpits somehow being depicted in a way which it feels more like "2D" than 3D. The forward canopy bars are humongous for both these planes, and a real frustration factor to the people who fly these planes. You can struggle to find a way aroud this by switching view angles with SHIFT+F1, but it still is severely limited.
In AH, while the cockpit bars are too thin, still it represents a more accurate "scale" of perception which would be closer to what a pilot sees in real life.
I'm not sure if I described this in a way people can actually understand..

, but I hope you can get the general idea.