I have always wondered why there isn't someone somewhere who has come up with a fix, well, fix might not be the right word, but an "improve".
Maybe like having the axle plated, or something like the shims mentioned. They knurl and peen to raise some metal. Along that line one might think peen with a punch, but the metal might be too hard, many variables. You'd have to be lucky or pure of thought.
How about drill and tap across the hub into the splined section. Then after assembly using a bolt as a plunger to force epoxy or JB weld into the joint. Like the song says, "nothin from nothin leaves nothin".