Having horses in the game would be nice because it's not OP because you have to feed it but then the advantage is obviously you travel on it. This has a up side and a down side. I know what the next question is, "how would you find one without making the game unrealistic?" Well, simple, just have built in farms on the map, just a few, and have animals in them like pigs and things and there, if you're lucky, they'll be horses. I wouldn't suggest having lots of grown crops on the farm or this would make the game a bit easy, and I understand you guys don't want that.