It was run in C'thun decks because it was decent, not because it was especially great. Also Old Gods has been power creeped to hell, its an incredibly weak set in comparison to the past few sets.
This is a weak card, through and through. Not enough heal effects in pally, and even then, cards don't stick around for long. You can't realistically expect to activate this effect more than once, if at all. Reminds me of new bolvar, who has the same issue.
4
This seems very clunky to me
2
You'd think this would be 1 mana