Avionics aside, the only difference I see is the numbers of levers you have to work with.
Training on a DA42 does not mean you can't fly a Baron or a Seneca. A couple of hours with an instructor and you are good to go. A King Air, which is a turboprop aircraft, requires a type rating and turbines are easier to manage than piston engines anyway.
Your skills will depend on your attitude. Are you a trainable person? Yes? Then you won't have issues.
Lufthansa use DA42 and for the latter stages of training a Citation.