Before the Warsong nerf, I ran a Patron Warrior deck that made use of a Gurubashi Berserker (2/7, gains +3 attack when it takes damage). It would synergize with Warsong Commander because of its initial 2 attack, and with only 2 whirlwind effects, it would become a powerful 8/5, which is a serious threat even if the turn does not result in lethal. In many games I played, it acted as if it had Taunt, often becoming the target of removal and silence that would otherwise have been used elsewhere.
I have a feeling that the answer here is going to be that it cost too much and put too much pressure on drawing Emperor Thaurissan to reduce its cost.
Best Answer
1) The combo was built around a single turn, so it was usually capped by mana, and it was rare that you would get out more than one tick of Emperor Thaurissian since board presence was usually fairly weak as a Patron warrior. 8 damage was very low for a Patron deck burst. It was not uncommon for a single Frothing Berserker to get into double digits, let alone two, plus all the charging patrons.
2) Gurubashi Berserker, while benefiting from self inflicted damage and the old Warsong Commander, didn't benefit from having a board full of constantly replenishing minions (Grim Patrons). It also didn't benefit from the ENEMY's board being full. The more minions on the board that get hit by whirlwind effects, the more attack Frothing Berserkers would get. Having two with full boards would get them +14 attack each for just one whirlwind. Gurubashi would only get +3 per whirlwind/self damage. Playing Gurubashi Berserker against an enemy's full board doesn't get you very far if you don't have lethal.