Being able to search only on Activity name or URL is limiting. It would be helpful to have other search field dropdowns. Searching on things like audiences would be very helpful in finding everyplace where a particular audience is being used.

When writing more complicated rules-based audiences it would be helpful to have a NOT or ANDNOT operator to be used. Additionally, providing an editable code view (similar to how Audience Manager allows) could allow alternate ways to write logic beyond the UI. 

We are also looking at something similar. Have you looked in the the new getOffer(s) function in at.js2.x? It's possible to deliver multiple regional mboxes in one call. However, our initial tests show a significant performance impact when compared to 1.x. Not sure the cause of the performance impac...

Agree. There are examples out there on doing this with profile script based on mbox name but that's not really relevant because frequency capping is usually done based on the content or offer not the mbox.