Repeat after me: GitHub is more than just Git. GitHub is more than just Git.

I would like to see Git be extended with a decentralized approach to bugtracking, code reviews, wiki's for documentation etc.

Isn't that Fossil?

https://fossil-scm.org/home SCM, bug tracker, wiki...

What do you need for wikis? Just put text files in a folder?

Bug tracking in git: https://github.com/MichaelMure/git-bug

Code review in git: https://github.com/google/git-appraise

Repeat after me: Git is more than just files. Git is more than just files.

Yes, it's also good a variety of different systems to store and address Markdown.

Which you could, you know, put in git.

Git is more than just GitHub though, that much is true.