Try pulling out the symbiote for a Gigantomancer and the Allosaurus Riders for Voice of the Woods. The only reason I respectfully offer this opinion is too put into your head the idea of creating lil tiny elf tokens then turning them into giants as they're attacking as a fast effect and then using the ones that don't attack too create your 7/7 elemental blockers.
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I got 2 EDH decks myself. One being Uril the miststalker and the other revolving around Experiment Kraj. Defeating Slivers CAN be done btw. Just out quick them. Didn't say it was easy, just possible >.>
This is actually about 100 times more effective as a green deck IMO. Awakening zone and everflowing chalices....I rest my case.