If its possible, i think it would be very helpful to get a on screen movable text/icon warning similar to how the addon ''castannouncer'' works that says when one of the spells you have listed to be indicated has been applied to someone on your raid frames.
For example, a raidwarning message that says '' LOOK AT YOUR RAID FRAMES DUMMY'' or a big ''!'' icon that appears when one of the indicators have been applied to someone on your raidframes.

The reason this would be nice is it would essentially be a reminder, telling you to look at your raid frames right when you need to and then you can locate said person in need of dispelling easier because we have the indicators. If possible adding in secondary option for only alerting when its people within 30-40-50-60 yards would be a very nice touch also .