add Cloudshift for the slime or to switch silverheart over to another creature. and id replace the savagery's for Revenge of the Hunted or Blessings of Nature .

hmmm i would rather not add a third color to the deck if i can help it, but if other people think it is a good idea i do have a playset of Glacial Fortress 's for splashing white.Blessings of Nature on the other hand seems like a good idea as i get to put the counters on several creatures.

-2 art dodge and add in vapor snag u got flyers good enough vapor sange basicaly does the same with life loss and can save you in late game

Interesting take on Delver... Staff of Nin doesn't seem to fit well, nor does Rampant Growth . No Snapcaster Mage ?? He'd fit well in place of 2x Rampant Growth .

You could play Trepanation Blade in lieu of the Staff of Nin . You'd get much use out of it.

Many of your Instants and Sorceries are 1x and 2x ofs. I'd pull out card:Hunter's Insight and Fog for 4x Ponder or Ponder as it's still in Standard until October... Your lone Naturalize could be a Gut Shot . You have 3x Naturalize in your sideboard. Mainboard, it could be a dead card, Gut Shot won't.

Hope that helps.