Citaro rear seat steps are pretty high
I still prefer KUB if die die gotta choose one, peak hour
loading is my first consideration.
Citaro can be configured to be able to take crush loads if
desired.
For the compartment before the rear doors, its possible to
configure it to side facing seats as such used in the kubs. Another
option is as per what is used in the Mark1 bendys, with only 1 seat
on either or both sides of the vehicle.
After the rear doors, if the rear facing seats are not wanted,
its possible to configure the seats at the wheel arch to 3 side
facing seats as used in the N113.
Samples of vehicle configured in such ways are available from
specification sheets from mercedes-benz's website.