I have never seen this thread before... But after seeing it, i still agree that the engine is too sensitive to high throttle inputs. I think that destroying an engine after 15 minutes of flying is very strange (what woud hapen to real WWII pilots on those long dogfights where the engine was constantly at the top?).
And now referring to the engine high temperature failure, you should learn some more with the A2A P51D (sorry to mention other sims), you should see a lot of smoke and fire coming from the engine, and it should start slowing down instead of stopping instantly (this is impossible due to the huge amount of kinnetic energy stored on the engine)....
I think these are the only things that are missing to make the sim perfect
Peace