Why freeze this in the object format?
Because if you put it in the object format, then it gets pushed and
pulled around, thereby putting generation numbers in every clone.
I'm starting to think put them in the object store, for exactly that
reason, and to start moving repositories in a direction where the look
more like they would if this had been done correctly from the start.
Then, because some operations are still going to create a lot of
traversals, a cache is always an option to improve the performance in
that area.