Since the "gold standard" for complex engine management is Il2, I will tell you something: It adds almost nothing to the experience. Only thing it really does is make going from plane to plane slightly more complex, having to learn the "sweet spot" settings for each. And it can be "gamed". If AHII added more complex EM, it wouldn't bother me in the slightest but it wouldn't add anything for me either.
OTOH, on some of the other things people call HTC out for being "unrealistic" on, they are entirely right.
WEP Automatic shutoff-Seems unrealistic though? But if you look at other sims, their solution for WEP limitation is automatic failure, which is even MORE unrealistic. Why? Because quite simply, there would be almost 0 chance of say a P-51D's engine failing if the pilot accidentally pulled 70'' for 6 minutes instead of 5. These engines could be and were abused *far* beyond book limitations without failure. "Realistic engine modeling" if such a thing were ever carried out, would effectively give every plane near unlimited WEP!!! HTC's choice to auto-limit power settings to book WEP limitations if anything actually forces AHII pilots to be somewhat *more* conservative of their power settings in actual combat than many pilots were, not less.
Cockpits-On the scale of an average sized monitor, an entirely realistic cockpit simply cannot do what it needs to do-let you read your instruments at a glance. Making the instruments larger and easier to read is 100% the right move to make. In AHII, we also have one instrument they typically did *not* have-the G-meter. This is a 110% brilliant and correct choice to make, because you don't have any *other* indication of G forces being pulled, sitting in your chair at home. It is ridiculous that *ALL* sims don't include G meters.
Trim-This is a biggie. HTC has on many occasions explained why CT exists-because trim is much more of a problem flying a simulator with small desk-top joysticks than flying an actual airplane! On top of that, you *can* use manual trim in AHII and it even has advantages in certain situations. Overall, while making you use manual trim (or not having trim in the roll and yaw axis available at all for airplanes that didn't have it in R/L, like in Il2) might on the surface *seem* technically realistic, in truth for flying on the com-pu-ter it would increase the difficulty of having a trimmed stable airplane far above and beyond what it is when actually flying.