Based on what? Assuming that what is being awarded is primarily the album itself, rather than the score or the show represented by the recording, I think Jersey Boys
is probably most deserving of the award.
What evidence have you got to support such a claim?
This is a completely different kettle of fish and I wonder how an award like this would go down. It certainly might (marginally) raise the profile of cast recordings and the competition would probably mean that we'd see cast recordings of a better standard. Not that all cast recordings are bad, but there are some pretty awful ones out there, some of which may have been better had they been vying for a Tony Award on their own rather than trading solely on the nominations or wins won by the show on the whole.