Unupped seems UP. Doesn't need to duo with air, I think a cost would be just fine. Even then it'll have more cost than Wardens.
Actually, the unupped is more a bit OP...
If you have enough pillars to pay each turn, it is an infinite dimensional shield which even stops Psions, Shards of wisdoms, momentums and shard of freedoms. And then, you can even play enchant artifact on it so that the opponent doesn't have a way of winning left.
Also, acording to the card text, this card only blocks your opponents creatures, but not your own.