Give us a description of why you built the deck and the reasoning behind your card choices. Then people can better help you improve it.

Thanks! I added info to the description.

Karametra's Acolyte can produce a huge mana ramp.
T1 - Forest + Mystic
T2 - Island + Kiora's Follower + tree warden
T3 - Forest + Karametra's Acolyte
T4 - Even with only 3 lands you can tap out for 12 with 3 from lands, 4 devotion from the Acolyte, untapped with Follower is another 4 and one from the mystic. Then you could play a Hydra Broodmaster AND monstrous it for 2... on the 4th turn!

I agree with theBGB Karametra's Acolyte can produce a crap load of mana if you need an example of how fast it can be, look at my deck Element of Treachery

Perfect, now we can make this badass!

Icy Blast > Crippling Chill; with your mana creation, Prophet of Kruphix, plus big guys, getting a ferocious on this to double-tap all their creatures shouldn't be difficult.

+2 Dissolve > Disdainful Stroke; I've found DS to be too narrow, I'd rather have a card useful in any situation.

Karametra's Acolyte can produce a lot of mana but I don't know if its best in here. There is already a few early rampers plus Kruphix, God of Horizons and Prophet of Kruphix. Personally I like 1-2 drop rampers so when I get to the 4 drop I can start playing my threats, not more rampers. A play-style choice ultimately.

-1 Prophet of Kruphix; unless she is integral to your win-con 2 of her is fine. The reasoning is once you drop 1, another doesn't add anything to your board.

What is your reasoning behind including Kin-Tree Warden? At only 2 he will not be as consistently drawn and I don't see what he really adds to your deck. If he is a early attacker I might suggest Triton Shorestalker or Hypnotic Siren (Siren is great all game imo) instead.

Thanks for all the suggestions! I'll replace the Crippling Chill with Icy Blast and Disdainful Stroke with DIssolve. I'll think about changing to 2 Prophet of Kruphix. I'll run 3 or 4 Karametra's Acolyte too. My logic on Kin-Tree Warden is to be able to use his regen to chump block without losing any board control.

I what do you think about Thassa, God of the Sea or Hour of Need instead of Archetype of Imagination?

Strong against burn/spot removal, and cheaper?

Thanks for the suggestion! As soon as I can get my hands on three Thassas, I'll run them instead of the Archetypes.