So I know this card seem kind of unexciting and expensive, but I think it could be a great card in PO. I think the ability to turn any of your artifacts into blue sources is very very valuable as that is often your choke point. Additionally his ability to act as a mana sink and potentially dig a few cards deeper (for a large mana investment) could prove to be valuable in certain tight situations. I think his biggest weakness is the fact that he is a creature, and a legendary one, making him weak to Karakas and other creature removal. If you manage to make him stick a turn or two then I think he can be extremely powerful at helping you chain POs and find you more action.
Edit: Just realized potentially the most important and broken aspect of him overall, he makes your artifacts tap for mana through Null Rod effects!