The healer in my FC I usually run with has a macro on his repose that places the ignore mark on the target so I guess I'm just used to it and don't see much of an issue with it. We found it useful in early dungeons but we never really use it anymore. It's just quicker to burn everything down. As a tank I'd rather have the healer concentrate on healing lol. The only exception being that when we speed run Bray HM with a scholar we've gotten in the habit of group sleeping the last mob before the first boss to lock them out rather than the typical pull.