How many real pilots have a 90 degree field of view packed into a 17" square, no peripheral vision, and no depth perception?
Hell, you would never be alowed to pilot a plane in "real life" if your sight was as restricted as what we have in these "sims". The view system has to be much more flexible than your head positions in "real life" to make up for the poor excuse for eyeballs that we have to deal with in a computer monitor.
Restricting the viewing system too much is far more "un realistic" than the awesome flexible system we have in AH now. The AH view system is flexible, configurable, and demonstrates the advantages and disadvatages of the various planes in terms of how easy it was to see out of them. That really is the point... to have the plane's attributes in terms of vision restrictions matter in the game.