Mayael is a great commander and it looks like you've got a good start. I do have four suggestions though...

1. Sylvan Primordial is banned in commander so you should find a replacement.

2. I think that you should add more power 5+ cards. Mayael's ability really works best with lots of power 5 cards. I run 31 in mine, you've got 25. I'd consider upping the ratio if you want to leverage her ability a lot, which it looks like you do. Even with manipulators like Scroll Rack I think you'll find that 25 is too few.

3. I would consider swapping out the Eldrazi. While annihilator is great, you'll miss out on their on cast abilities if you cheat them onto the field with Mayael, Quicksilver Amulet or your other tools. They are still really good, so keeping them isn't the worst, but I'd think about it. Alternatively you could switch to simply adding a lot more ramp and plan on hard casting them, although I think their may be better commanders for that.

4. I'd consider adding some more ramp. While your mana base is really solid, I think you'll find yourself wishing you had more mana available. You really want to have 6 mana before turn 6 and I think you'll struggle to do that consistently.

Check out my deck Mayael the Anima EDH if you want some more ideas.

Thanks for the feedback Abaques! I was looking for an place for Karametra, God of Harvests anyway, so i will def drop the Primordial (thought i caught all the banned, haha).

I think you're right about eldrazi, at least the the Artisan of Kozilek since it's so painful to hard-cast and the main upside of the card is casting it.

I'll def check out your deck for ideas. thanks again :)