A crazy, over-the-top dressage simulator would actually be rather fun. Well, it really wouldn't be a "simulator", more of an "exaggerator". We can have horsies doing kickass russian dances!
Or better yet, let the horse do the riding and let the stupid jockey do the dancing. See how THEY friggin' like it! See, already we've made a better game than some "dog sim" that sounds more like a furry circle-jerk orgy fantasy. Eeeeew.