And really that's just it. Transformers isn't just about robots that transform into stuff. Heck it's not even solely just about their personalities (which some people here like to stress) since they're just classic "good guys/bad guys" not much different than Masters of the Universe or anything else. It's about ICONS that a lot of us grew up with.
Look at Masters of the Universe. That was a whole new "reimagination" on another beloved franchise (a franchise possibly even bigger than Transformers at the time). In and of itself it wasn't a completely horrible movie... heck the fight between Skeletor and He-man at the end rocked (as I'm sure Prime and Megatron's will in Bay's movie)... but, it just wasn't Masters. It wasn't "right" at all. I have a feeling the same is happening here.
It's just too radically different to kindle any sort of affinity. But, then I guess Transformers was way lame to begin with, right?