Rate my MTG Magic The Gathering Green/White/Blue Sliver deck?

Get rid of the mistform warchiefs and mirror entities. By the time you come to that part of the game you will be killing your opponent anyway. Add more coat of arms though. If you can get 4 creatures out with 2 coat of arms they get +6/+6 each. That's plenty to kill everything. I would suggest a couple of walls or maybe a couple of wrath of god type cards just to slow your opponent down because sliver decks have always been slow to start but kill everything when given the chance. Also if you can get a couple more ancient ziggurats in there that would be awesome.