Maybe this card prove be more useful than Hagatha, too many times you suffer with hand size limitation with bad spells in hand, this card is far less random and reliable and complete the quest is very easy.
Am I missing something or does this just seem meh?
You are missing the fact the quest is extremely easy to complete with the new 2/3 draw a card and x4 minions give you another x4 minions (lackeys) with battlecrys, and after complete you get doubled value every turn.
It is not the new quest rogue but it is pretty strong, control shaman maybe shift from Hagatha to focus in Shudder.
Quest is very easy to complete with the abundance of battlecry minions and right now shaman doesnt utilize their base heropower so I can see this just being a defining card of shaman for a while. 7 mana hagatha and her generated minions just become lategame value bombs. This card will find a home somewhere and if not wild will probably greatly appreciate it.
Paying 2 mana for the effect shouldn't be ignored. For example, 8 mana 6/5 deal 6 damage for a Fire Elemental is not OP. It's still strong, but on a fair level. With more smaller battlecries the hero power gets better, but then the shaman's hand is empty and card draw is not shaman's strong suit.
I don't expect this quest to be overly strong. Tempowise, if you finish the quest as early as you can, you have minus 2 mana tempo every following turn if you want to benefit from it. And only a few cards in hand.
Edit: And hero cards have an anti synergy concerning the hero power. It's either the quest, or hagatha/thrall hero power. Not both.