A +1/+1 counter deck and no Kalonian Hydra ? Shame on you. Shaaammme. In all seriousness though, a 4/4 trampler that turns into an 8/8 when it attacks and also doubles all of your other counter creatures is insane. Only problem is that it is just above your mana curve, not counting the bestow cost of the saytr. Just something to consider as a major win con if it doesn't slow your deck down.

I love Kalonian Hydra, and use him in most of my green decks. The point of this deck is to rush with as much damage as fast as possible and finish them off with Aspect of Hydra

If you can afford them, Garruk, Caller of Beasts would be amazing. Each +1 would draw you 3-4 cards.

Gyre Sage is not that great, And neither is Swordwise. Trade Gyre sage for a few Kalonian Hydras

And this is Mono Green with quite a bit of Devotion. Revenant Hunter is a MUST for this deck.

Now, I know this sounds very strange, but a Good Ole DerpDear (Brushstrider) Is a pretty decent Card for this kind of deck. 3/1 with vigilance for 2 mana.

Overall, pretty good deck, +1