One thing I didn't like about his list was the 4 Jace Vryn's Prodigy, which is great (and is a good 2-drop to play on 2, unlike Snapcaster Mage) but doesn't crew Smuggler's Copter; whenever I play my build I don't feel like I have enough cards to crew Copter reliably on 3 (which is why I've added 2 Meddling Mage).
I had the exact same thoughts about the deck -- it's a really cool combination of a lot of pet cards that I love, but Jace's inability to pilot Copter and the overall relatively low number of potential pilots bothered me. Beyond Meddling Mage, what other options have you explored?
EDIT: Upon further investigation there are 14 cards capable of crewing Copter here, 4 of which are at 4 CMC. This makes for an 83% chance of drawing one to play by T3 after a T2 Copter, or a 95% chance to find one to play T4. Critically, both of those calculations ignore the cantrip effect of Thoughtscour as well as the looting effect of Jace, so both probabilities are likely higher in practice. I'll have to play with the deck more, there may not actually be much of a problem with pilot reliability after all.
EDIT: Upon further investigation there are 14 cards capable of crewing Copter here, 4 of which are at 4 CMC. This makes for an 83% chance of drawing one to play by T3 after a T2 Copter, or a 95% chance to find one to play T4. Critically, both of those calculations ignore the cantrip effect of Thoughtscour as well as the looting effect of Jace, so both probabilities are likely higher in practice. I'll have to play with the deck more, there may not actually be much of a problem with pilot reliability after all.