First, Chapter I lets you choose the most threatening noncreature artifact from each player to turn into a 0/4 Wall artifact creature with defender in the hopes that, once Chapter III comes around, you will destroy all of them (along with any other Walls around)
The Mechanist, Aerial Artisan Tacking Clues onto every noncreature spell you cast makes The Mechanist, Aerial Artisan some of the most consistent Clue production we've ever seen in the command zone, and mono-blue has the tools to break it
Interestingly, the above example is not the only combo that you can run with this deck and all of them can be as deadly as this one
If you enjoy swinging tempo with one play, Gisa is a great pick
A lot of my opponents will draw for turn prior to remembering to pay the 4 for Paralyze, getting a big advantage off of that added information
I also kind of like the effect here, since a lot of Dimir spells can be really scary if they're copied