I believe blocking while healing is a bug on the PTR, they intended to make blocking work when using instant casts or drinking a potion NOT when using spell with a cast length. It happens quite often when they "attempt" to fix one thing they break something else. I'd be surprised to see it go live with full blocking working while casting a heal.
Stoicism on live is huge because it applies to all spells cast including blessing of freedom/protection when cast on anyone in your team. 30% harder to dispell/purge BoF or BoP on your teams mates yes please. 30% change to have mass dispell not remove your bubble etc.
I haven't tested stoicism on the PTR recently so no idea whether they are "fixing" it.
This many paladins can't be wrong:
http://www.geekboys.org/arena/index/...ladin/all/all/