The only wires I use on my ebike are the two battery ones and the one for the throttle. Don't plan on using the others ever - lcd display, brakes, etc.
can I just cut off the unused wires without harming anything at all on the controller?? I just want things a bit neater without a wire mess.

Probably not a problem as long as you wrap the small loose end with tape to insure there is no contact which might cause short. Ask at endless sphere for something more definitive or maybe DW will answer.

No on/off switch on the display? Must be a pretty basic controller if you can start it w/o the display connected. Some of them need certain wires connected. How would you shut down the motor if it took off on you? That could happen if the ground wire on your throttle breaks. At least one brake switch is handy.

Anyway, for the wires you're not using, It might be a good idea to write down the wire colors and keep the connectors, so you can re-use those accessories if you ever change your mind.

Don't cut with baterry connected. I done that once. Kapow.

I've found that the clump of wires from the controller can be hidden with a wrap of Velcro (I use a cut down chainstay protector). I'll try to post a picture later today.