Big screens are an OK workaround for no passenger windows, but they still have to contend with severe structural pressurization challenges, strict emergency evacuation rules, and incompatibility with current airport gates.
In a conventional aircraft you sit on the roll axis. In a blended wing body design you can have off-axis motion that can increase motion sickness. Rather than rolling with the longitudinal axis of the aircraft, you move up and down when the aircraft banks. Not necessarily a deal breaker, but an additional difference to deal with.
This sounds fixable in avionics and training. (Shallow, gradual banks.)
Note, too, that a larger lifting body needs to bank less to execute the same turn as a craft with more loading.