I think what's really lacking for me about the designs and the faces in particular is they all look the same.

There's too much detail, too many lines, too many edges, ridges. Its too busy. And that makes telling the faces apart difficult because there's nothing instantly recognisable.

The other thing is Bay's fast editing makes it even harder to see the face.

And here's my point without being able to recognise the expressions on their faces its that much harder to make a connection with them. They're characterless robots.

I think it was a good idea that Optimus actually has a face. We need to see him talk and convey expression. And it's just as important to see this when the TF's are doing battle. The designs and Bay's fast editing just makes this impossible.

Its why Sam Raimi had Spiderman lose parts of his mask in the Spiderman movies. So you could actually see and feel what the character is feeling.