Nah, I think thats just the color filter they chose for that particular shot. The thing is the figure they made looks good with that color scheme, I don't see why they would be so hesitant to translate that into production. I mean a purple bot can't be that much harder to light then sayyyy, a bot with a black paint job or better yet a Blue Bot with Bright red/orange flames.
I'm kinda curious about the mouth animation as well. But it kinda has me nervous too, I'm afraid they'll over compensate the lack of facial expressions in Shockwaves design with over zealous and flashy mouth animation....which already looks too bug like. thats something I've notices for a good majority of the

designs in this Bay-verse. They all have very insect inspires design schemes. Even those that are suppose to be mixed with other anthropomorphic types (Ravage/Panther) have bug eyes..or eye, side mandibles, pincers, bettle mouths...hence why with Shockwave I kind of hope he has no mouth animation. He's just there to be what he is;
A Big Bad Bot with a Big Bad Blaster
Quick movie prediction, easy $ that Shockwave has his eye popped or shot at some point during the climax of the film. Just seems like something Bay would do ha ha ha