Unless the goal is to just introduce artificial limits/penalties on
rebirthing, this does not make sense. What if a non rebirthed player made an
eq, then reinc's 5 times in a row without gaining any exp. Now he has less
total exp than when he made the eq. Should he not also be penalized in the
same way? Same could be said for the suggestion of not letting them party
with people worth more exp than themselves.

But like I said, if the idea is presented as a method of adding some
difficulty to the rebirthing process, then the comparison to non rebirthed
players is pointless; however, I think there would be better techniques of
adding such difficulty to the process than the ones you recommended (assuming
it is needed at all, which I don't think it is)