One useful item would be support for multiple RCS systems simultaneously.

Example:

• root refs: git://.... branch wiki
• master refs: git://..... branch master
• dev refs: git://.... branch dev

I'm not sure how the mechanics would work out for choosing between what to refs and managing branch self-references (though doesn't ikiwiki do something like this:

• 1
  • a
    • j
  • b
    • Page : refs a/j
• 2
  • a
    • j
  • b
• a
  • j

Ikiwiki checks: 1/b/a/j, then 1/a/j and succeeds...

The new git subprojects might work, but I've had trouble making them work sanely in the past...