> I do prefer the "do one thing and do it well" approach.

I prefer the "do what you do well" approach. If it's one thing, or many things, doesn't matter, as long as it's both efficient and correct.

I mean, if Fossil fails at some of these things, then we can criticise it for its failings, but it appears it actually does the things correctly.

The comparison with GitLab is quite enlightening. Fossil is a few MB, and Git + GitLab (to be feature equivalent) is a few GB and requires far more resources. Then which one does what it does well?

Now, there are a few things I don't like from Fossil, like the lack of a cherry-pick command. I have no intention of using Fossil over Git. I am just stating that criticism should be based on actual misfeatures and not on development "philosophies".