Personally, I thought the logical way to watch Sky TV on a TV is via the Sky set top box. After all, that's what it is designed for and you get to view ALL the channels of your subscription.
Sky Go is designed for mobile, on the go viewing of select channels. It was never designed with streaming to large screens in mind or as a substitue for multiscreen. It is a secondary viewing method.
If you want a primary streaming viewing method, that is what NowTV is form hence it's support for Apple TV.