I didn't have any big problems with AHM and I really liked Drift. It's pretty uncommon these days to get a new character in Transformers Fiction, Drift isn't just another Gun or sword, he's someone who's done a lot of Bad and if I recall the story properly, was undergoing a lot of soul searching and self doubt as a result.

Perhaps not the most original character in modern fiction but seriously how many new characters have there been in the last decade that can't have some element of their character considered a reflection of something we've already seen.