Oh my god! Lets see if I have got this. Because of the decision to fit an electronic injection diesel, rather than a mechanical one we will need:
Two alternators per engine (one for the aircraft electrics, and a PMG alt for the FADEC) and that means two separate alternator drives (gears or belts)
Two FADECs per engine and the associated wiring to interconnect with the aircraft system and the other engine.
That is a serious amount of extra kit which is going to have a weight penalty, OK for twin jets, but we are talking GA aeroplanes here.
Perhaps there is some kind of buzz in flying a little aeroplane with all that electronic stuff, but is it reliable? It seems like the difference between the latest Audi TD which can only be serviced by experts, and a Peugeot 205 which is totally reliable and easy to fix by it's owner.