You literally gave us a tank that's perfectly capable of healing himself, without any specific cooldown as far as I can tell. I've done each of the trust Dungeons once for story purposes and it's been a slog everytime 'cause I'm just hitting my one DPS button ad infinitum for 30 minutes.
Normal DF has been fine for me. It doesn't feel as good to heal as it was at the end of SB, but I'm still having fun, but man they didn't think about how brutally boring trust Dungeons would be for healers. Thank God for healer insta-queues right now.