The only issue I see is that for 4 less riding you can have a horse that has one less speed than a courser. Perhaps this is balanced out by the weaker other stats of that same horse?
The main purpose of this horse is to transfer you from point A to point B. I.e. moving a high-strength tincan from spawn point to ruins on the Field by River map. Or for taking any other important position on any of game modes. This horse has only 37 maneuver. As you know, maneuver defines how fast your horse accelerates. So having the weakest maneuver among all the horses these 45 points of speed mean that it will be hard to reach that speed. Also it will mean that this horse will be very difficult to control on that speed, so it's the best to travel from point A to point B. Also it has the weakest amount healthpoints and armour among all horses which makes it a perfect target if you try to move around enemies, 1-2 arrows and it's dead. Also the weakest bump, so battle capabilities of this horse are very low.
the tarpan needs more hp ... or it will get weaker than any horse ... I would say 85 hp
It's supposed to be the weakest horse in the game. It's a cheap solution for those who lack agility and need to travel fast without facing enemies.