Hearthpwn

You shouldn't craft a Hero, since you already have several of them (and most of the good ones) so I would keep saving dust for the next expansion. If you really, really want to craft a Hero in this expansion, though, here are my 2 recommendations, based off of which Heroes you are currently missing.

Valeera is useful in a lot of Rogue decks, even if it may not look like she is. She supports her class well, which most people did not think at the release of KotFT, and I think many people still think she doesn't support her class well. She doesn't change the playstyle a lot, but playing her in a deck will change how you play the deck in the late game. I personally recommend her first.

Rexxar would be my next recommendation, as he can constantly generate creatures for you to play, giving you something to do every turn, and making it harder for your opponent to be able tell what might be coming next. Even though you rely on RNG for the creatures, you'll typically get at least 1 good creature to build with.