Originally Posted by 
laststepdown
				 
			Gnaw and Aura Thief were both suggested by my teammate while digging through an alpha-deep collection for 5 people's decks. I wouldn't recommend Gnaw without Sun Titan to get back LED, as getting 3 mana is far-fetched, and you want to win or have game on table by turn 2, effectively. He convinced me when he noted I could pay the flashback with LED, and recur the mana easy with Sun Titan (other cards we were possibly going to run in that slot that didn't make the board: Crippling Fatigue, Psychatog lol, Sadistic Hypnotist, Darkblast, Firestorm number 4) Going up to 11 5 color land was because in testing, I wanted to cast either Putrid Imp, Cabal Therapy, Firestorm, Wispmare, Ingot Chewer, and of course Faithless Looting. All on turn 1, all the time. I sacrificed the explosiveness of 4x Cephalid Coliseum to support the resilience of the deck-which included, as you mentioned, zero copies of Breakthrough in my 75. I had a long discussion with Feldman on facebook about the first 60, and he mentioned he was running zero Coliseum, 4 Undiscovered Paradise, and sideboard all the copies of Breakthrough (he recommended 3 vs combo), to add to consistency, since draw 2 is usually enough to win against decks that aren't combo. He disagreed about running any non Grave-Troll targets for Dread Return, but I felt Sun Titan recurring Golgari Thug's death triggered ability and Cabal Therapy meant I could probably recur the Lorwyn anti-hate evoke kids all day. This is probably much easier done with Tortured Existence, but none of the dealers had any, so whatever. I went with zero Breakthrough, because not only did I not need it, I had enough discard outlets that I didn't have to One for Nothing myself to do anything relevant-like Careful Study while keeping a Faerie Macabre in grip, nullifying a Snapcaster Mage completely. Or holding on to a Firestorm vs RUG Delver, or keeping Wispmare back against Enchantress.
Overall, I could have easily played -2 Chain of Vapor, +2 Wispmare, but then I may have had to run -1 Aura Thief, +1 Angel of Despair.
As for the spell portion of Cephalid Coliseum, no. I never missed it once. I actually left one copy in as you notice, just in case I could recur it with a Sun Titan, and didn't have an LED-Faithless Looting in the graveyard, or if I had an extra open mana. Most of the time I would just win by Dread Return on Sun Titan-bring back Thug-Therapy, sac Thug, trigger Thug, put anti-hate or Narcomoeba back on top, continue mind twisting them.