Offhand I hadn't even realized there were still chunks of Vector in an extension since it got merged in as a skin! :)
More than the naming issue, it's important IMO to make sure that units that belong together ship together and get enabled together. That definitely ties in with the concerns about support burden.
Merging the ext bits to core makes sense on that basis, since the skin itself is in core. The bits in the ext seem reasonably self-contained and I don't think it would be much of a code review burden.
However I am sympathetic to the idea of keeping Vector-specific goodies together as their own module. For future versions it might be beneficial to bundle things like this together as standalone plugins that include both the skin and the other code; if the infrastructure for bundling extensions with the default install gets in, this can be a good way to modularize and can reduce the work of merging things to *core* when we really just want to *ship* them.
-- brion