@Kroisse I'm not with you. How types are serialized in JSON are not just implementation detail, but sort of what users have to be aware of. If it's just implementation detail we should remove enum and boxed because they can be generalized using union and record.
Although there could be better alternatives to unboxed, I believe unboxed is way better than boxed at least. If we don't have enough time to search better candidates than unboxed I still suggest to rename boxed to unboxed. (@admire93 has coded that uses boxed keyword at @spoqa, and we're getting less opportune to rename it day by day.)