Love it! I've been messing around with this idea in my head but never got around to building the deck. I do have a couple of ideas though.

Why not have 4x The Wanderer ? Seems like your whole gameplan falls out without her, so you need to be getting her as often as possible.

Realm-Cloaked Giant instead of Kaya's Wrath ? Much easier to get in a tri-color deck than having two mana each of two colors.

Maindeck Once and Future (or similar) and Bolas's Citadel . You need to be able to get cards that you've milled out of your library, and Once and Future helps with that. The sad thing about that is that most graveyard recursion spells target creatures, and you need to be able to fetch planeswalkers too. Bolas's Citadel is similar to Command the Dreadhorde , but it gets you stuff from your library and is a continuing effect rather than a one-time use.

You also need some cheap stuff. Right now your curve is very high and you will die to most decks before you even have a chance of getting off your combo. The Wanderer and Command the Dreadhorde should be near the top of your curve, not the middle. I understand this will take a lot of rethinking, but it's a necessary change. You could also theoretically add some ramp, but I don't think that's the direction this deck needs to go.

I might recommend Scheming Symmetry , since this deck is very heavily focused on getting the pieces you need (and doesn't have much of a backup plan).