For or against natural horsemanship
For or against a specific piece of equipment (ie. Spurs, double bridles, polo wraps)
For or against various floating (trailering) methods (ie. Using a divider, tying or not tying)
For or against starting (or could be jumping) a horse before 4/5 years old
Personally I think I would probably go with the already suggested to breed or not to breed or to slaughter or not to slaughter. You can go way more into depth with those topics than you can the ones I've listed, which can be a godsend when you have to write X # of words.