Id switch Rootbound Crag and Copperline Gorge counts around go x4/x2 and not x2/x4 cause later in the game Rootbound will help alot more {for somereason I get real lucky to get lands like Copperline quick and in one deck I only ran one}
not big one the preist. yeah it pays for itself but for a 2/1 in a fling deck for 3cmc I'm not to into it.
Wall of Torches 
imo would be better cause of the 4/1 or 2cmc would work better and if you needed it late game i could take out something bigger.
land is a must. I dont like the 15 even with the elves and the birds maybe cut creaturs down to 3 (minus the birds) and add some more land. 7/7 isnt much but a improvement. maybe find a way to add
Goblin Arsonist 
in the mix. you can fling it if you need to or block with it why you have to.
Also glad you have a deck like this. IDK if this works they way I read it but
Chandra's Phoenix 
should probably find its way into any fling deck. cause its addition cost sac a creature, then deal damage. so if it works right Summon it/Attack/Fling/Get back (Someone tell me if this is right or not)
hope this helps
