Remand: Huge tempo swing early game + cantrip. However our 2 slot is jam-packed as it is, difficult to fit this in from experience. Additionally it's difficult to hold up two mana.
Delver of Secrets: He's great turn 1 and if he flips turn 2. We don't have the ability to fix our draws like in Legacy though, so something like 40% (forgot the exact statistic) of our games are pretty bad since he doesn't get to flip immediately all the time. The deck is well tuned for him though, would switch out Thing in the Ice
for him. I've just had more success with a slower (but not durdle) game that Thing calls for.
Cryptic Command: hurts. Maybe sideboard. More suited for control lists.
Thoughtseize: Like Jund, we need to manage our health carefully. Unfortunately we aren't as fast as Jund, having explosive starts isn't what we do. I think it's better to stick with IOK.
Young Pyromancer: If Gitaxian Probe, Ponder, Brainstorm, and Cabal Therapy were a thing in modern... He gets going but it's pretty slow. Thing in the Ice
fits better imo.
Mana Leak: Might replace Rise/Fall and Collective Brutality with a couple of these. Can't run too many counters because we tap out maybe half the time, save a mana for bolt or push.
Dismember: Might move one to SB, but haven't found the need for it yet.
Collective Brutality: Swapped out for Vendilion Clique
Pack Rat: I loved this card back in the day, but he's too slow.
Painful Truths: Great card, but don't know where to put it or if we need it.
Death's Shadow: Might be good if we throw in Thoughtseize MB, but that might not be what we want with this deck. Need to test more.
Electrolyze: Lots of value, but proven to be too slow with our 20 lands..