With Raise, it's ideal to let the healers handle individual deaths. When RDM and SMN should jump in is when there are 3 or more deaths, or when deaths are happening back to back to help for when healer Swiftcast is down. Casting for 8 seconds isn't even possible during many mechanics of a given savage fight. It's tricky, though, cause these situations where caster Raise holds value are pretty rare and have to occur during instance where multiple people can die but also not wipe the raid.