What would be useful to have?
Allow use of Set Theory to manipulate or filter combinations of segments and tags.
The current filters rely on me having table columns that represent each of the segments. I had to allow for the possibility of people being in more than one segment, so I needed a table column for each segment. I manipulated each of these segments and column filters individually, to check overlapping and underlapping contacts.
eg MyList contains segments Members, FreeList and Delegates. When I imported them, I expected only Members in Members, only Freebies in FreeList, and only Delegates in Delegates, but I had some contacts in more than one segment and the counts of contacts in each segment did not add up to the total.
A basic test like {Members ∩ FreeList} = ∅ (empty set) would have been very easy to understand and would work towards a nice, clean contacts list.
Maybe SQL is Where Members and FreeList.
Maybe you have this functionality already.
I just re-mapped my segment columns to Booleans, and that seemed to work well.
I would like to see the ability to create and assign tags to transactional mail messages. Currently, most if not all my transactional mail has the tag set to none. It would be good to be able to create rules that would be for example 'if the subject contains this string:« xxx » then assign this tag to the message.
I believe this would add a tremendous ability to create new segments and mail targets.