Deice
I agree that things are moving in the right direction, but stuff like the required carriage of an ADF is beyond anybody's control. I know an ADF is a piece of junk (except perhaps as a compass locator on an ILS, but do you really need that?) but that isn't the point. Same with GPS approaches - we don't have them and are never likely to, well not to places which don't already have conventional approaches (which incidentally are in the existing GPS databases anyway
) all the time the CAA more or less mandates full ATC for an instrument approach.
A capable IFR aircraft unfortunately has to live in the
European framework, backward as this might be.
One very unfortunate thing is that the guinea-pigs required for debugging any diesels will all have to be dug up from the small European market. None of the makers are going to take a chance on blowing their names in the US market; apart from that there isn't any fuel cost advantage over there.
Personally, I'd go for a carbon fibre airframe, with a +10G -10G design limit, put a 750SHP PT6 on the front (to hell with it not having enough aileron authority at Vs to overcome the torque reaction at 100% power; doesn't the pilot have a brain??), full TKS, bizjet type avionics with FOG gyros, an A4 sized MFD running Jeppview/Flitedeck... might have a bit of a problem getting it moved from the US Exp category to a Permit though