[jD91mZM2]

Not sure I understand the question correctly, but here goes:

My personal bias is to keep using submodules or at least subtrees where possible, mainly because it's builtin and because it's written by smart people. This is mostly for when repositories are pretty big and you don't want to submodule/subtree the entirety. But that's just me.

I hope the maintainer complexity is as low as any other git solution, all the rebasing tools are just using standard git so there should neither be any advantages or disadvantages. The advantage of using this is to not check in everything into one repository (perhaps avoiding accidental modification of unrelated files that could cause merge conflicts).

[narnianal]

My impression is that monorepo got popular because submodules are too complicated to use on 3+ projects combined together. And I don't mean that the user interface sucks or that it's illogical to use, but most people will tend to use rather less submodules than more, even experienced git users. Therefore I think the breakthrough will come with someone who really understands submodules but has a great idea how to simplify the process. I hope this project may be a step in the right direction. Therefore I want to know more about the internals.

[jD91mZM2]

I'm afraid I'm not the messiah you're looking for, then. This is not a replacement for subtrees/submodules. But from my limited experience I agree with what you're saying :)