So I'll say that I don't love this card, and I think the spirit of what 13NoVa is saying is right, a 5 mana card needs to do a lot in vintage.
That said, I wouldn't want to undervalue the "untap two lands" part of the card. Dr. J is right that the card is VERY strong with Mana Drain, and perhaps also with instant speed draw. I bet you could do something interesting with this card if you started with 4 Mana Drain, 4 (instant speed draw spell .... Thirst for Knowledge? Gifts Ungiven?).
I like that this card doesn't have the natural tension that so many planeswalkers have where you want to build up counters but also take advantage of the best abilities. It's pretty easy to play this and +1 it until you get 8 counters (and very likely win from there). If you build a true draw-go deck, this does some things that a Jace or a Tezzeret can't.
That said I don't love the idea of a 4 Drain deck right now, so it doesn't get me worked up personally, but there are some people who are always going to play as controllish as possible and this could be a good fit for them.