Worldspine Wurm and Dark Depths? Just so you can have the satisfaction of playing the two largest creatures in EDH

I've currently been trying to get my hand on both of them, they fit really well with the theme of this deck and when paired with something like Pathbreaker Ibex it's just ridiculous.

Primal Forcemage?

I dunno, it doesn't do a lot on its own, might net me a card draw now and then, but I'd almost certainly prefer another large creature in its place. Maybe if I can trade for Concordant Crossroads, but until then, it just seems like a low-impact card.

Maybe a Squall Line for a potential mass kill with all that mana. I like it over Hurricane because it's an instant. Love it in my Omnath, Locus of Mana deck: "Oh, Omnath is at 20 and you're killing it? Okay, 18 damage to all players and flyers." Can also be used non-lethally to get rid of pesky flyers that green has trouble with.

Ya well, it was budget until Selvala's price shot up like a rocket.

Needs more yisan

I have built a similar deck and I love it. How do you deal with flying though?

Other than Akroma's Memorial, nothing. Do you have any suggestions?

Uh, other than the usual green sorcery cards that kill all flyers, I'm not too sure. I wanted to add a bunch of creatures with Reach, but it's not too easy to find good ones that will fit in this deck without taking out other good ones that are already in it. It's a real pain...

Hurricane would work well based on what you said, and if I go infinite mana (Sword of the Paruns, Umbral Mantle) and I have more life than them through Shamanic Revelation or something I can just kill everybody. Any ideas on what to take out?

Personally, I don't like Creeping Corrosion as it often destroys my stuff as well.