Is unshallowing any more expensive than a normal clone? The shallow clone is for the benefit of the user so they can get to work sooner.
It is, because of the way the server has to recompute packfiles. I realize that you may choose to optimize for the user over the server, but a partial (blobless) clone should satisfy both.
Does the server rule out sending a packfile that you only need 95% of? That seems like a good thing to optimize.