Kind of a good idea. Decks that have a two pronged attack generally are--here it's damage from immortals plus unstable gases. I recommend the following calibration:
-1

pillar, -1 phase dragon
+1 dimensional shield, +1 immortal
I wonder why you chose this deck over a mono

with

mark though. Immortals and phase dragons are notoriously expensive because they come out quinted--I would prefer flying EEs with pay-per-use creature control and deflagrations to disrupt your opponent's setup.