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.
The ability to find entities in order to modify them (activities, offers, audiences, even recommendations) is something that the Adobe Target Product Management team is looking to improve. Your feedback is helpful toward this end! Thank you and please feel free to share any additional details.