Nah I am changing him to Vorinclex actually. My deck isn't very ETB based and I have a ton of other ways to remove non creatures, so I'm going with the mana doubler instead.
Yeah I think Terastodon makes sense for you. He still blows up three things, although he doesn't ramp, and you can't abuse him as much because he gives your opponents a horde of elephants. I would say Terastodon is a fair version of Sylvan Primordial.
A couple card which might make this deck even crazier is planar guide (from legions) he's like a threat of ghost away for a one drop. And turn to mist, another blink effect (from shadowmoor)
Why the heck are you running Emeria, the Sky Ruin? You only have seven Plains so you would have to get every single one in play for it to work. 99% of the time it is just an ETB tapped Plains that you can't tutor for with basic land tutors.
It's so much better for only one more though. Think about it when one of the creatures is Eternal Witness or Archaeomancer. It becomes a consistent 3 mana blink and it doesn't rely on soulbond like Deadeye Navigtor.
I've seen it done several times, but the best choice is probably Jenara. Angus McKenzie is cool but really expensive. There aren't a ton of great choices I guess.
nuff said
Also you have 101 cards.