The development of GIT evolves quite organically, following the interests of the community, and the guidance of Junio. There is no central resource to understand where things are going, unfortunately.
Here is an attempt to collect links to previous discussion threads that have "This is a reasonable way forward" decrees:
- Adding a way to even more blindly trust the result of 'rerere' (http://article.gmane.org/gmane.comp.version-control.git/85231)
- Differentiating 'precious' from 'ignored' (http://article.gmane.org/gmane.comp.version-control.git/185746)
Please add links to more topics, but make sure you do not clutter the list with vague hand-wavy wishes that are not backed by a concrete "Here is how we would implement it".