Gorehowl is one of the reasons I think CW is often favored. But it depends on what late game the priest is running. Since priest cannot effectively beat aggro and control with the same deck list, I think it's just weird to hear someone say CP is favored vs CW. I think 99% of CW lists run gorehowl and justicar, so it's simply difficult for the priest to actually kill the CW and they're typically the aggressor in the match simply because of how much health they can stack before getting into fatigue.
Two things have changed slightly with Karazhan: Priest of the Feast and Bishop.
The Bishop offers two bodies for the price of one and effectively lets me place two threats on the board with one card (as opposed to two pre-Kara). It makes it easier to put pressure on the CW. The second is Priest of the Feast. While the life gain isn't significant outside of Fatigue, the 6 health is. It quickly moves out of range of Gorehowl (along with Blademaster and all other Blademasters that get Resurrected).
If it's a Resurrect Priest (which is what I'm playing now), I can often afford to be reeeeaaally greedy against Control Warrior. Sometimes I won't play creature until turn four, five, or six. I played a game today where my first creature was Bog Creeper. From there, you can really abuse Resurrect and Bishop.
The hardest Control Warrior build to reliably beat is C'thun Warrior because they can often sneak in a Brann before C'thun and just burst you down. Or build up a huge C'thun and then finish you off with Grom or Gorehowl.
I've been doing OK with Rez Priest against both aggro and control. Though it's not consistent. The first few days I played it, I enjoyed close to a 70% win rate though it's gone down quite a bit since then.
Tempo Mage, almost any kind of Rogue, and Hunter are still really rough. Aggro shaman is a bit easier and Midrange Shaman is a constant struggle but doable...