At the very least, CVD pilots should be permitted to hold a Class 1 medical with the following restrictions:
CAT MPA OML as FO only
(Commercial Air Transport Multi-Pilot Aircraft Operational Multi-Pilot Limitation as First Officer Only)
CAT SPA VCL
(Commercial Air Transport Single-Pilot Aircraft by Day Only)
Once an ATPL is held, with >100 hours Night Flight and on successful completion of an assessment flight by an appropriate TRE, the first restriction should be removed.
I don't see much to be gained from aiming for too much to start off with but the above would seem to be a reasonable compromise.