Is adding red to mono blue something to toy with? For some reason I thought {purphoros, god of the forge} and mono blue would be pretty devastation, especially with a resolved master of waves
I doubt it would work consistently. Splashing red just for the two card synergy IMO isn't worth it, especially since you could use that four spot for so many other things that would be beneficial to this deck.
Mono blue devotion also is based on the fact permenants are blue. So if you could keep them all blue but wanted red or any other color spells and keep the curve accurate then by all means.
Run {Purphoros, God of the Forge} and 4 {Steam Vents} sideboard to punch them in the throat when they lest expect it