Eric,
Hasselblad has been smart to keep their H3 system closed in order to rectify the mediocre
performance of some of their lenses.
The 35HC is a dog with out correction.
The 28HC was designed to be used with correction,nothing wrong with that!
However it all depends what you shoot.
If straight lines are not an issue,don't worry to much about it.
Also,you already have some great Rollei lenses,so stick with it and upgrade to a Hy6.
I haven't received my Hy6 body yet to use with my eMotion 75LV,therefore I haven't been able to test my Schneiders ( 40+55PCS+ 60 + 80/2+90 Apo and 2.8/180)
However I'm pretty sure that 40mm will give me straight lines,I'm not that worried about the others.
Cheers,
Willem.