Comment 5 for bug 170825

Zooming is perhaps the most common operation of all, text or
no text. And it's certainly much more common than typing
numbers with the keypad. And no, zooming with mouse when I
have my hands on the keyboard sucks, thank you very much.
And of course we can't use function keys for zooming, as
they have no zooming semantics whatsoever and are all used
up for tool switching anyway.

You can try discussing this issue on the mailing list. If
you gather an overwhelming majority in your support, I'll
change it (or rather make it optional).