There is still no technical reason that 240/4 cannot be rehabilitated, other than continued immaterial objections to doing anything at all with 240/4, and given the rate of IPv6 adoption thus far, if not for those, it could possibly be reopened as unicast IPv4, and be well-supported by new equipment, before the percentage of IPv6-enabled network activity reaches a double digit percentage...
Don't most IP stacks (still) consider 240/8 and above "illegal addresses" and won't deal with packets to/from those addresses? If that's still the case, it'd be another good 10-20 years before 240/8 and above could be released for general use, as nothing would work with them. In that case, you might as well start rolling out IPv6 and any new hardware/software changes ready for v6.