I think for a film to fall into the 'worst' category, there needs to be a significant disjoint between the reasonable expectation a film creates and what it actually delivers. Disappointment seems to be a huge factor when voting in the Razzies.

RotF was a mess even by Bay's very ordinary standards. The difference between what should have been produced with that level of talent and resourcing and what actually ended up on the screen was vast.