Mithun pointed out that I'm only proposing how to move trunk here, not the branches, tags, and site sections. These will need to be moved as well. I don't think it makes any sense to merge these into Hive, Especially since we want to be able to release a 0.5.1 in the future if we need to, or if users wish to continue to build off of the existing branches without taking in the merge into Hive.
So, I modify my proposal as follows: I'll move all of the existing HCatalog code (trunk, branches, tags, site) into hive/hcatalog/hcatalog-historical. I'll then move/re-arrange ONLY the trunk section of the code, as outlined above. So when I'm done we'll have the following: