Sidisi EDH

Suggestion 1) I would remove any artifact ramp, except MAYBE chromatic lantern and replace them all with creature-based ramp like sakura-tribe elder, fertilid and yavimaya elder (not technically ramp but you get the idea). A large portion of non-creature spells that have creature counter-parts should be replaced with creature based spells in order to maximize efficiency of the commander.
Suggestion 2) Because the deck is self-mill based, Birthing Pod loses a lot of its power due to the nature of inconsistent mana cost chains. It's a card that is powerful in its own right, but might not be suited for this deck.
Suggestion 3) I would definitely incorporate any flashback spells that are relevant: Tracker's Instinct and Forbidden Alchemy are both able to enable Sidisi and can still be used even if you mill them off a separate ability.
Suggestion 4) I feel like your sorceries represent a sub-theme of BUG control, but certain spells run counter-intuitive to the primary plan. Such cards include: Damnation, Black Sun's Zenith, Gaze of Granite and Devastation Tide. I get the idea, but once I reach four mana, I want to see Sidisi in play. So these four cards mean giving up your own board presence, which should only be done if you're being outclassed. I could see running one or two big spells such as Cyclonic Rift or In Garruk's Wake which affect only the opponents' boards, but any mass removal runs contrary to your own game plan. However, in contrast, if you remove the majority of your artifacts you can justify running a creeping corrosion and/or a Back to Nature as sweeper effects for non-creatures. However, you might be able to utilize enough creature based removal with cards like acidic slime, woodfall primus and terastodon to justify avoiding such cards.
Suggestion 5) I would consider looking at cards like Hell's Caretaker and Phyrexian Delver to replace a few of the more lack-luster reanimation spells that are in the deck. Once again, using creatures to replace non-creatures to maximize the deck. Likewise, certain self-mill cards like Armored Skaab make for reasonable defensive creatures which add to the self milling plan. You could also consider some of the dredge creatures, such as Golgari Brownscale though they are admittedly lower in power-level.
The following is a brief list of cards in the deck that I don't find particularly impressive for this build: Consuming Aberration & Vulturous Zombie (These work amazingly together, but this deck isn't supporting this type of game-play.. but an argument could be made that they are powerful enough on their own to keep), Kruphix God of Horizons (You already have reliquary tower and excess mana is not particularly useful in this build much of the time), Green Sun's Zenith (The spread of green creatures is unreliable due to the nature of the deck, but the card can be useful for cards like reclamation sage and acidic slime, so it's not necessarily bad), Sultai Charm ( I'd rather run Shriekmaw or Nekrataal in this spot)