As of right now, I don't think this card is going to be great. There's simply better options right now to end games for a control deck. That being said, once the DKs rotate out, this card could potentially see play as a finisher. Right now however I do not have high hopes.
If a card like Dragoncaller Alanna can see play and this card is basically just that but with more snowball potential and easier summoning conditions, then I bet this card will see play as well.
The difference is, Alanna is a card that rewards you simply for playing spells you would anyway. This card (at least with the hand buffs we know of right now) requires setup in the form of at least one other card to buff him in your hand, which is a dead play until you actually play him. Their power level is not even really comparable unless warlock gets some SERIOUS hand buff support....and we know how well that worked out for pally.....
You will have to work, to get it to 5/5 with two soul infusions. At that point it might be playable. If it ends up the far left card, and you dont die before turn 8. I still think its a bad card and will see fringe play at best.
Too slow for zoo. Not gonna be played in control. Only way this sees play is if they print an even handbuff card, in which case it could be a powerful board splash for an archetype that doesn't have many ways to go wide.