The thing to note that in many of the quests that play a 5 mana 8/8, that will /only/ be the card that needs to have removal on it. Hunter will play very low cost minions, ditto for shaman. The Priest's deathrattles so far appear to be generally lower cost minions. Paladin will be buffing low cost minions, and you might not even be able to target Galvadon anyway with stealth. Druid is possible, I guess, but most of the minions in that package will be at 5 attack.
Basically, if you have non-BGH removal in most cases it will just be used for the 5 mana 8/8. And also, there doesn't seem to be a lot of targets for BGH except if they both run and complete the quest, and if they complete the quest you might have already lost.
Since there are so many 5 mana 8/8 maybe we will see BGH in most decks just as if it was DR. BOOM Meta?
Possibly for classes with a narrow range of removals, but even then I quite doubt so. Spells are generally more versatile.
Don't forget that during Boom meta BGH costed (3), not (5). It is the nerf that killed BGH, more than the meta.
Before the Msog meta a serious rag action was going on and i didn't see any bgh so maybe not.
I think it will (but depends on the new meta)
look:
first of all, everything is possible with Adapt
Ultrasaur
King Mosh
Dinosize
Free From Amber
Charged Devilsaur
Kalimos, Primal Lord
Swamp King Dred
Volcanosaur (chance with adapts)
Giant Anaconda (possible) + they might use some classic cards like Deathwing and more
Frozen Crusher
Bittertide Hydra
Sabretooth Stalker
Elise the Trailblazer (possible) RNG
The thing to note that in many of the quests that play a 5 mana 8/8, that will /only/ be the card that needs to have removal on it. Hunter will play very low cost minions, ditto for shaman. The Priest's deathrattles so far appear to be generally lower cost minions. Paladin will be buffing low cost minions, and you might not even be able to target Galvadon anyway with stealth. Druid is possible, I guess, but most of the minions in that package will be at 5 attack.
Basically, if you have non-BGH removal in most cases it will just be used for the 5 mana 8/8. And also, there doesn't seem to be a lot of targets for BGH except if they both run and complete the quest, and if they complete the quest you might have already lost.
My guess is that it won't see a lot of play.
http://www.hearthpwn.com/forums/hearthstone-general/general-discussion/188924-bgh-will-come-back-in-the-ungoro-expansion