I'd like to suggest abusing Siona's ETB trigger with cards like
Strionic Resonator,
Ephemerate,
Conjurer's Closet, etc. I think you can take out a couple basic lands to make room for some of these if interested, as she only costs 3 mana to cast. Furthermore, all of your spells are very cheap (very low average cmc of 2.5) so you can comfortably shave a couple lands.
Depending on how much you want to play with the infinite combo, you could use more tutors like
Idyllic Tutor (it's $6, but its price will likely fall once the set is printed) or
Enlightened Tutor (it is ~$20, though)
Also, one major shortcoming of a lot of EDH decks I see is a lack of removal. You do have a category for removal, but because you have very few removal pieces, you won't see one consistently. I suggest having 5 cards that can deal with creatures and 5 cards for artifacts and enchantments. Cards like
Generous Gift that can deal with both count for both, allowing you to conserve deck space. Here are some of my favorites (flexible, instant speed removal spells are the best)
Generous GiftBeast WithinSwords to PlowsharesReturn to NatureNature's ClaimHere are some options that fit more within your deck:
Oblivion RingGrasp of FateConclave Tribunal