Dies to Removal

As long as you throw away any 1 land hands you'll be fine - that's a pretty conservative curve.

I'd run more non-creature mana rocks over the Myr. It's not like you really need them for attacking and you probably won't get the chance when everything in the deck kills them anyway.

Are there specific reasons why Oblivion Stone, Decree of Annihilation, and Destructive Force didn't make the cut? I'm guessing mana for the latter two, but I don't see a lot of reason to not play O Stone. (Btw, I'm including Decree for the Instant Armageddon + Card mode... you probably don't want to be Exiling all your Indestructables)

Also, Sunforger would give you a lot of nice toolbox options.