Optimus Prime's characterization wasn't off, he had the same voice actor for pete's sake
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Bumblebee, yeah that was different, but honestly I like it better. They were on this track with Cheetor and Hot Shot who basically took the role of "everyone's favorite buddy". I like Bumblebee being a badass though, but ya'know a loveable badass.
That said I would ditch the speech gimmick and find a good voice actor for him. It's time. In a way it's grown on me for Bumblebee to have a schitck, the radio thing is incredibly charming but I just feel like it locks his character in too much.