I've seen this suggestion before, but I believe it needs more attention.
Create a companion mechanism that allows us to replicate companions from our own alts.
Years ago, the original Guild Wars did this in one of its latter DLCs. I found it particularly compelling and continued to play the game long after GW2 was launched.
With all the gripes about cloned companions, this would certainly solve the problem. I suspect, even if ZOS nerfed the hell out of them, companions comprised of our alts would be much more useful.