Elder Scrolls Online said long before launch they would have a store. So far just having a horse is a way of not creating "Pay to Win". Its a luxury item. Much like how they could add fun "Costumes/Disguises". Of the many things this Store could add I personally like to see "Name Change" & "Appearance Change". If you wanted to be more detailed you could have a ingame Barber that cost Gold and a full Character Customization via the Store for real money.