I think the current trend towards "failure modelling" is fine as long as it isn't put there as a substitute for other more important features. After all, FSX is not a simulator for mechanics, it's a sim for pilots! If I fly a real aircraft, I rarely concern myself with mechanical problems (that's sorted out by the servicing engineers back at the hanger) and provided liberties are not taken with engine or flight controls, most aircraft nowadays are incredibly reliable.
I'm not into random failure modelling but I would like to see failures when I've taken mechanical liberties. One thing I would like to see is carb icing modelled well, it's insidious and can creep up on you.
The best thing any sim aircraft can achieve is to give you as close as possible a feeling that you are controlling something which communicates the visceral feedback in the real thing. That has always been our goal and has a bigger priority than engine covers opening, switches clicking, or mechanical features which are not primarily concerned with flying.
And I have to say you hit that goal!! Having recently gained my MEP I have to say your Duke is the best piston twin on the market, My only wish is it that it had been a Duchess