Unlike all other accelerators in Thunar, which are configurable via gtk_accel_table, the "Backspace" key is now hardcoded to perform "Go to previous visited folder". I'd like to be able to somehow (not necessarily via gtk_accel) reconfigure it to perform "Go up one level" and thus mimic other other desktop environments' behavior.

Getting used to using Alt-Up for this is not a sufficient workaround as it is a slow two-hands-on-two-keys combination, while backspace is quicker and also a lot of users (migrating from other DEs) are used to it. Anyway, having all accelerators configurable should be a goal for any user-friendly app.