When a McQuarrie Concept Snowtrooper and an Imperial Snowtrooper love each other very very much, a stork will bring them an Imperial Flametrooper in nine months.  That’s what the Imperial Flametrooper appears to be.  It looks like the mask and cowl from the McQuarrie Concept Snowtrooper added to an Imperial Snowtrooper, and then armed with a flamethrower.  I’ll take one and so will you.  I don’t think this sort of thing is derivative.  It’s finding ways to weave McQuarrie concepts into the cinematic Star Wars aesthetic similar to the Rebels AT-DP Driver.  I like it.