Yeah, my thought for that was to simply write a wrapper for Rules conditions/actions if possible. Think about it like this:

1. CA invokes a hook to load all available conditions.
2. Any module enabling the hook can return the condition data. It just has to be in the right format.
3. Rules uses very similar data structures, b/c we based our CA work off of Wf-ng (at a time when Rules wasn't anywhere near a release).
4. So, the core CA module can implement hook_ca_condition(), invoke the comparable Rules hook, and massage the data so that it's compatible with CA.

Now, this isn't necessarily the solution we should implement, but it's a thought that could help overcome the duplication difficulties but still allow us to develop CA as a more tightly integrated system w/in UC.