Three mana is a little steep for this effect. Once he is online it seems super cute to mill two, theb dakblast out the creature you want, but what are you really accomplishing? You're making your dorks cost 1 less and have flash for the low low price of 3 mana and vulnerability to yard hate.
This guy is an awesome tool for a Heroic deck in other formats, turning useless enablers into bodies, but I'm not seeing him in Vintage.
I don't do 'cute', the ability to flash creatures into play (in this case from the graveyard) seems very strong to me. Think about situations where you need to quickly rebuild board presence. If you have build up 4 mana and you topdeck this dude with darkblast in hand and an active top, you can quickly get back destroyed and countered creatures in 2 turns. And note that each time you darkblast, you are potentially hitting more 2cc creatures and you can animate them in play for

(at instant speed).
The card is very interesting and was one of the last cards spoiled. I have followed the threads created so far, and this one is actually one of the more interesting cards that could be discussed.
This new set has surprised me a lot with really strange new idea's/prints. A lot of these new cards have a mysterious side, there is something 'unclear' about how they would play out in games. I think this is a fantastic way to design. It is not easy to make assessment and this card seems one of them.