I don't think that you will survive against aggro decks or decks with many creatures after probably four or five rounds. It takes a little bit too long to dish out the Planeswalkers and you won't have any defense against opponent creatures if your opponent choses to actually attack your Planeswalker instead of you. Also, you would have to spawn a new Planeswalker every round to make up for the one that was killed before (if you have some in your hand or even enough mana).
So after all, it looks like a fun casual deck, but not really up against most of the decks nowadays.
Things that could give you some time:
Ensnaring BridgeOblivion RingThings to get more bang for your buck:
Rings of Brighthearth