Is there an option to allow the mouse wheel to zoom in and out instead of the “1” and “2” buttons? It doesn’t seem to allow you to remap it to a non-keyboard key.
(More so because this would allow my wacom’s scroll wheel to zoom without reaching for the keyboard)
no 
No on the mouse wheel, although this has already been submitted as a feature request.
Regarding the wacom scroll wheel, though, you can program it to scroll with the 1 and 2 keys, so that should still work.
~Lilly