2) By taking EF you are replacing an ability - Word of Glory - with a shitty version that only does 70% of the healing but has ticks. "Situationally" if your AP is so high that your heal is all overheal, well, go for it, but otherwise you're doing yourself a disfavor over just taking nothing at all in that shitty tier.
(I understand perhaps it may still be an HPS gain as a tank, but we are "looking past the meters" (remember, ghostcrawler?) and realizing that as a tank, mitigating spike damage is much more important than some mostly overhealing, tank-healer-sniping ticks.)
Right now in reality, Holy is the only class that's looking at some shitty Hobson's choice where you can take 1 of 2 shit tier talents (that basically amount to taking nothing), or take a 3rd talent that makes your ability "maybe" better, and likely (in many situations) simply a trap.
New record even better than the old mage 90 talents: I don't think there's a single fucking talent in game right now that actually takes an ability that you currently have and has the potential to make it worse. Glyphs? Perhaps. Talents? None, until now.