There are a lot of really cool ideas for new patch types:

 - bug-tracking patches
 - hunk moves
 - tree patches (eg. XML)
 - ... and more!

The problem is that whenever you want to define a new patch type, you
have to define how that type commutes with all other patch types.  There
must be some better way.

I don't know how to pin this down to a concrete verifiable next action.
 It seems to just amount to "think really hard" (about what this kind of
infrastructure should achieve and how...)

It looks like issue1096 may be one of many components of this
infrastructure; however, I want to be careful to point out that for me,
this is more about what goes on in the darcs core than the more mundane
(but still necessary) details about patch formats and what not.

I've plugged a half-baked idea about dividing patch types into
insta-commuting regions on http://wiki.darcs.net/Ideas/PatchPlugins