I don't watch trailers - screenshots tell you much more. The trailer is trying to compete too hard against the other trailers out there, which are always going for maximum impact with no regard to telling you about the game experience.
I thought it made some sense to have one screen for the touch controls, and the other for the main gameplay. Many, many games used this feature on the DS. This was a benefit that the PSP lacked. (I still preferred the PSP though).
As gargantuan as it may be (just how big are we talking anyway?!), it's nowhere near as big as a tablet - and they seem to be accepted for all their girth.
so_hai's comments