I second this and I have been asking for something similar for over a year. At the VERY LEAST make it so Casual Mode doesn't cause the horde to chase you, because sometimes this game is outright unfair in placement of zombies and it's really frustrating NEVER being able to get to the damn gallery.
And to the people saying "just knock them over and roll past them", that doesn't work half the time and I end up just getting stuck in a conga line