Just as a pointer, whichever side you are taking, make sure you make your arguments both reasonable and logical - not emotional, and not wacko, both of which will discredit your position.
As to other things to look at, IMO the "use or abuse?" debate is possibly the most interesting, challenging, and controversial. And nowhere do you see it more than with horses. Where to draw the line between use and abuse is really an intriguing debate...at least to me...