After testing the list above a little bit, it seems to me like splashing both blue and black is worth it. The cost of running two extra shocks is minimal. Thoughtseize in the sideboard helps a lot against other linear decks and helps you dodge boardwipes in the grindier matches. Plague engineer hasn't been that usefull so far, but I can imagine this card doing work against Infect, which I suspect will be played a lot.
https://www.mtggoldfish.com/deck/2012876#paper