Ian Jackson (along with Sean Whitton) has posted a manifesto and status update to the effect that, since Git repositories have become the preferred method to distribute source, that is how Debian should be distributing its source packages.

Everyone who interacts with Debian source code should be able to do so entirely in git.

That means, more specifically:

1. All examination and edits to the source should be performed via normal git operations.
2. Source code should be transferred and exchanged as git data, not tarballs. git should be the canonical form everywhere.
3. Upstream git histories should be re-published, traceably, as part of formal git releases published by Debian.
4. No-one should have to learn about Debian Source Packages, which are bizarre, and have been obsoleted by modern version control.

This is very ambitious, but we have come a long way!