A lot of criticism was weighed against the first two Transformers movies when they showed robots transforming into ridiculous crap like cell phones and computers. But that swings both ways - in the old-school days, we had robots who changed into things as crazy as cities. Metroplex was a gigantic robot who transformed into a whole Autobot City. Can you imagine how a live-action representation of a whole city changing into a robot would own? It'd be like that bit in Inception only it would make sense.