I get that you can work around the problems, you don't seem to get that from a math point of view, rebase forces either a) a centralized model or b) you have

I get that you can work around the problems, you don't seem to get that from a math point of view, rebase forces either a) a centralized model or b) you have to throw away any work based on the dag before the rebase or) c) you have the history in the graph twice (which causes no end of problems). (a) is the math way, (b) and (c) are ad-hoc hacks. You are well into the ad-hoc hacks, you've found a way to make it work but it includes "don't do that" warnings to users. My experience is that you don't want to have work flows that include "don't do that". Users will do that.