Naga Giants wrecks control and midrange so damn hard that you have plenty of room to throw in all the anti-aggro tech you want. You can basically make aggro 50% winrate like that and still keep your 90% winrate against control.
Wrong. The Giant deck has a lot of counterplay. Try playing it.
First of all, if you're aggro, you're mostly favored. The best variant of Giants vs aggro, Druid, is still unfavored and it's gonna get gutted as the nerfs come. Sure, Pirate warrior will be nerfed as well, but aggro shaman is potentially even better against it cause of devolve countering Spreading plague and taunts in general and much higher burst from hand with lava burst.
Second, there are giants that are good against control (clockwork, mountain) and giants that are good vs aggro (molten, sea). Molten and Sea are basically unplayable vs any control player that know his shit. In Giant druid, since you have the least manipulation, your giants will often be too slow to avoid clears from the control list, and innervate going is gonna reinforce this problem even more. Mass ramp will also make mountain usually cost mana even with naga out, which, again, open for counterplay. The only real strong giant in this situation is clockwork, which however is a dead card vs aggro.
Giant Hunter is much more consistent in getting giants out with naga on T5 thanks to tracking, elekk and tracker, but it run 0 decent anti-aggro tools, with the best one being easily avoidable ones like scientist->explosive, and then it has no way to stabilize after playign giants, as it play neither heals nor taunts. Also, no actual card draw means that on T5 you won't put down enough damage to kill your opponent in one turn, meaning aggro has virtually up to T6 uncontested, which in wild will just leave you dead.
I've played both decks a significant lot, and none of them felt too good to me. They're just insanely highrolly in the sense that IF you draw naga and IF you draw the right giants for your matchup you're probably gonna win, which is really not that much different from any deck which isn't a slow control one. They absolutely kill certain decks, but it's nowhere as "inevitable" as quest rogue was pre-nerf (since that deck could easily OTK after quest with gang-up patches for example) since it's much worse at reloading, and quest rogue was unplayable in wild anyway. Lots of people at the beginning just played wrong against it, like attacking with control decks making molten playable instead of just waiting to slow them down enough and giving you time for answers.
Just as example, decks that are doing good vs it:
- highlander priest which i still think is the best deck right now in wild
- dudes paladin, both aggro and midrange, which play double equality, or even single equality but a faster deck. Not clearing dudes fast and often means that dudes paladin is potentially the fastest aggro deck around with stegodons and buffs. Equality can also easily clear a giant board, and spikeridged steed gains at least two turns which are all you need as an aggro deck to finish the job.
- aggro shaman. No giant deck has a favorable MU vs this, with Druid losing its best tools against it in the nerfs (plague+ innervate). After the nerfs, the deck will be an absolute dog to it.
- aggro druid. No questions here, aggro druid lose innervate, but can just lower the curve and go even wider. No giant deck is racing this.
As for other decks:
- renolock can play bloodbloom twisting or just play a 4 turn mountain/drake + PO + shadowflame
- control shaman is dead, but it probably was already dead because of jade druid
- same for control warrior which also lost one of its best cards gg.
- jade druid is heavily unfavored, but plague + doomsayer is still a 90% clear against giant decks. This may be an actual buff in disguise to control decks since jade druid has much more inevitability than giants whatever which can only flood the board twice in a game.
All of this may not apply to Giantlock, since i've never played or saw it, but i have a suspicion that it may actually be the deck that could break the card as it has insane consistency from its hero power to play both molten and mountain regularly no matter the matchup, and play them in droves.
Also, honestly, the meta (in wild) would've been more balanced if they didn't touch either axe or hex. But this is another matter.