Uril, EDH

Thought Vessel seems like overkill. I probably draw more cards in my Sigarda enchantress deck (I have Enchantress's Presence which you don't, and I run stuff like Flickering Ward for repeated draw and Hunter's Prowess beyond what you have) than you will here, and there aren't many times I can think of where Reliquary Tower wasn't enough. It's not a bad card, and I'd run it if EDH ran 125, but I have a hard time including it in a 100 card format.

Obviously Serra Sanctum is great, but it's now a 50 collar card which is annoying.

Replenish is better than Retether in almost all situations. Yeah, it's 13 bucks, but it wins games. Then again you're only running a couple of non-auras, so it's probably not THAT much better in this particular deck, but it's still better.

Sigil of the Empty Throne can get out of hand in a deck like this.

Short of an aggro deck like Edric or something I'm not a fan of mana dorks like Birds of Paradise or Bloom Tender. I guess it depends on the meta, but I hate seeing my ramp go away to the inevitable turn six board wipe. I'd much rather run a couple of mana rocks or land ramp in those slots, or even enchantment ramp like Wild Growth and Overgrowth (which feed Serra's Sanctum, Ancenstral Mask, Ethereal Armor, etc.). But like I said, that's meta dependent. I see a ton of board wipes, and not that many mass-enchantment wipes or mass land destruction. Maybe you get Birds of Paradise to stick for 8 turns.

I've found that in a three color deck Exotic Orchard almost always is a dual land, if not an outright tri-land in multiplayer games.