There's no doubt in my mind that precision is for more for ADCs or just any AA-reliant champion. But, does Overheal help tanks? I've always had a fondness for Dr. Mundo and was wondering if his insane health regen would count as "excess healing" once these new runes rolled out.
i am just glad it stops at 8% of total health
i wouldn't need some 20k shield 
with 
showing up
Frankly I'm enjoying how split up the runes are into trees. Some trifecta of runes which would otherwise synergize stupidly well are inaccessible because they're in three different trees. Can't have overheal and ravenous Hunter unless you're going to give up resolve and lose out on revitalize, font and grasp. Riot's done a good job keeping things separated just enough you can't hilariously overspec into a single trait.
I don't think tanks will benefit from overheal though, simply because tanks usually have large infrequent heals rather than the constant Regen afforded by lifesteal.
Mundo's ult and innate are both simply HP5. His only healing is his Q.
I don't think any other tanks self heal in a way that would generally happen at full health.
There are some new runes that heal so maybe some combinations will include Overheal.
Would you run Precision on any tanks though? I guess Presence of Mind could help with laning.
If you have a way to get that healing, yeah.
Most tanks don't, though, but you could try for it if you have an enchanter support.
Keep in mind, healing from others counts for 300% towards the shield, so it is nearly a must have for games with Soraka(if you can use other runes in that tree that is).
