You’ll never get serious discussions about this unless you talk about how this IP block will be distributed if it became unicast space. Otherwise this is no different than the other 10 times this has been proposed.

The main issue has always been the logistics of defining a brand new allocation policy that won’t run out of IPs in 6 months, because otherwise nobody is going to bother spending a bunch of money to support an address block which will most likely not even work anyways.