I'm just kind of speaking off the cuff here (i.e. not real thought out or set in stone plans), but it seems to me like the conditional actions system can continue to be tailor made to our needs. This will allow Ubercart to ship with something smaller and specialized, kind of like the catalog module. However, when other modules are enabled, the functionality is either expanded or in some cases replaced... like when you enable Views and make a custom catalog. I realize that's a little bit of a stretch, because I don't see enabling Rules totally replacing CA (since the function calls are hard coded in our modules), but it could be the way that CA is extended to work with any number of other contributed Drupal modules.

Also, I'd encourage you guys to check out the core code in ca.module. The code that loads the data and evaluates predicates seems to be less confused than what I've found in Wf-ng / Rules. I'm sure there are things we haven't thought of that Wf-ng had located and resolved through much use, but I also feel like Rules might benefit from the code we've developed for this. Ideally we'll keep making it smaller and smaller, but right now it should be pretty straightforward and well commented. (The exception being the code that you pointed out for converting Wf-ng configurations to CA predicates.)