Can I has?

Okay, so my initial impression of your deck yielded some cards that are of questionable use. They are as follows:
Roar of Challenge - Low synergy
Order of Succession - Can be used against you
Metallic Mastery - Not many artifact creatures unless playing with Kell
Illicit Auction - Likely to hurt you unless you include more life gain
Cleaver Riot - Low synergy
Thassa, God of the Sea - Low synergy
Smelt-Ward Gatekeepers - Only 3 gates means likely to do nothing
Kolaghan Forerunners - Situationally useful
Hivis of the Scale - Not many dragon creatures
Atarka, World Render - Not many dragon creatures
Atarka's Command - Good, but low no synergy
Aura Graft - Situationally useful
Crypsis - Low synergy
Dragonshift - Low synergy
Flash Conscription - Check legality due to [W], but probably okay because it's not a cost.
Gruul Charm - Low synergy
Savage Beating - Neat, but low synergy
Sheltering Word - Too temporary for a long commander game, I prefer permanent hexproof
Temur Battle Rage - Low synergy
Tower Defense - Situationally useful
Tibalt, the Fiend-Blooded - I have two of this guy and I've never kept him alive long enough to use his ultimate. I'll trade him to you if you want him.
Sword of Feast & Famine - Expensive and low synergy
Thran Dynamo - expensive for colorless mana, there's probably a comparable one with colored mana
Furnace Celebration - Limited usefulness, 2 mana for 2 damage is so-so and you'll probably use the mana on spells instead.
Heartbeat of Spring - Are you sure you want to give everyone mana? You don't draw as much, so it could work against you.
Might Makes Right - You don't have many huge creatures, may not help often.
Primal Cocoon - Why include this without Forced Adaptation or even Momentum?
Retaliation - Okay, but better in mass token decks
Risky Move - Funny, but not always useful
Sight of the Scalelords - Low synergy


***** Cards that I Suggest *****
Fecundity - Drawing cards
Rhystic Study - Drawing cards
Mirrorworks - Copying creatures
Minion Reflector - Copying creatures
Riku of Two Reflections - Copying spells
Djinn Illuminatus - Copying spells
Dominus of Fealty - Stealing creatures
Mirror Sheen - Copying spells
Charmbreaker Devils - Regaining spells
Mnemonic Wall - Regaining spells
Elixir of Immortality - Restocking your library
Glaring spotlight - Removing hexproof
Arcane Lighthouse - Removing hexproof
Homeward Path - Regaining control of your creatures if they get stolen
Marchesa's Smuggler - If you really want unblockable, here's another one that gives unblockable, though there are a lot if you want me to enumerate them, I can.
Assault Suit - Funny to watch a creature continually traded.

** Alternate Sacrifice Outlets **
Goblin Bombardment (1R) - Deal 1 damage (Free sac)
Ashnod's Altar (3) - Add 2 colorless mana (Free sac)
Cold Storage (4) - 3: Exile a creature you control; Sac Cold Storage to gain control of all creatures exiled this way. (Lesser Conjurer's Closet)
Carnage Altar (2) - 3: Draw a card
Demonmail Hauberk (4): Sac a creature to Equip: +4/+2
Junkyo Bell (4) - Target gets +x/+x until end of turn where x is the number of creatures you control. Sac a creature during your end step. (Free sac outlet and a slight buff).
Altar of Dementia (2) - Mill (Free Sac)
Barrage of Expendables (R) - R: Deal 1 damage
Blasting Station (3) - T: Deal 1 damage, nice because it's colorless direct damage
Culling Dais - Sacrifice to draw

Forced Adaption is strictly better than Primal Cocoon.
Chamber of Manipulation for stealing.
Bow of Nylea to buff your commander.
Beastmaster Ascension for buffing your commander and your creatures.
Pyromancer's Goggles for doubling spells.
Rootwater Matriarch for more stealing, maybe combo with Krasis Incubation.
Tibalt, the Fiend-Blooded for obvious reasons.
Maybe Dack Fayden.