All that it really says is that Warriors are easier to pilot to 2.2k than rogues. It really doesn't mean that rogues are bad in any way, and to be brutally honest, they weren't. Warriors were just so derpy faceroll OP that everyone who wanted easy arena ratings rolled one. Why would anyone besides the most hardcore rogue fans continue playing something that's more challenging to be successful with?
Plus there's the whole fact that in Season 12 rogues were heavily countered by warriors.