many current bots don't use click to move but the (normally) protected wow api calls (e.g. move forward / backward / turn, etc)
if click-to-move would be disabled, the other ones could rather easily switch to this method, too.
a very simple way to ban lots of bots is to have gm's work at night and require people to answer a gm if contacted.
so... if someone received a ticket and a gm tries to contact that guy he is REQUIRED to answer a question. if he doesn't answer at all (or just random stuff) BUT is still fighting, walking around etc they should be allowed to ban him for botting without further questions. maybe give 1 warning if he hasn't been caught before.
problem is: blizzard doesn't ban bots cause they would lose money.