I have a few mods that you can get from curse-gaming that really help tanks.   One is called taunt buddy.  If your taunts are resisted it flashes to whole raid/part etc.  If you've been in zg with me ot'in im sure you've seen it.  The other is somthing called tank points.  It basically rates the gear you have for tanking.  I have found it useful and it is accurate.  Enjoy :-)