Another feature I would like to see:
The ability to delete dependent records without a repeat region. If I have a table of shirt groups (adult, child) and a separate table of sizes tied to the groups by a foreign key (adult:s,m,l,xl;child:s,m,l), and I allow deletion of the record from the WADA form for the shirt groups, it would be nice if I could delete multiple records from the sizes table based on the id of the record in the group table being deleted without having to have a repeat region to do it.
Perhaps, call it delete dependent records instead of delete multiple records. You could also include a feature to check dependent tables which would be a validation that prevents the deletion if any dependent records exist.