Sub Rogue is ruined since Legion redesign, it's a pruned joke.
And Pika doesn't even play Sub anymore he plays Assassin now, which is an even bigger pruned joke. It's like a Frost DK with poisons, very brainless but does big numbers so.
But watch some of Pika's MoP era videos (they're on YouTube) and you will see some incredible plays.
Current state of the game is awful.