Maybe I'm just not running dungeons like crazy, but I never see these healers that DPS so much that the tank dies. Occasionally I'll run into a moment where the tank dies and we have to restart the pull, but not only is that incredibly infrequent, but even when it does happen, there's a very simple solution. We do the run again a little slower and all is fine. So we added 3 minutes to the run, oh well.