As a healer I really appreciate the way you think, and imo, that's what makes you a good tank, just that you care.
I've been in some terrible parties lately who just don't give a rats ass about adds surrounding me during boss fights, and then afterwards even go on to complain about that I died.
It's also the DPS's job to get the adds off, everything is better than my heals being interrupted and causing a wipe. It's not that hard to heal a dps or two at the same time, at least not in the early dungeons.