Whew. I'm glad they learned that lesson.
What they fail to realize is that the other metas are still superior.
http://ptr.wowdb.com/items/95347-sin...primal-diamond - Heroism proc for casters.
http://ptr.wowdb.com/items/95344-ind...primal-diamond - Barkskin proc for healers.
Obviously it depends on the proc chance and ICD, but from a healer perspective i'd much rather take a heroism or barkskin over 3% more healing.
Also, your point about iLevel is correct. But if item upgrades are brought back in, you could upgrade and then use the meta or as you said, just use a PvE helm and drop a gems worth of Resilience and PvP Power equivalent to 1% healing.
Considering it's an PvP gem with only PvP stats they can easily adjust it to make it stronger if too many people are using the PvE one. But thank god I don't have to raid to get the gem.
i do not think the 30% buffs will be active in pvp outside of RBGs/randoms and world pvp as its too strong.