Tall punishment => mostly neutral => loss of devotion bonus
If any faction had it own Morkvarg, pinging down any boosts with ease - then it would be fine.
There is plenty of Tall punishment in Factions, even more so than SK, NGs cards are all punishment basically, tons of Poisens, Vincent, Invocation etc etc.
ST has Poisens, Plenty of removal, can take out engines.
NR has bloody baron, Similar to Morkvag, only advantage of Morkvag is the Synergy, but alone these two are the same.
MO doesn't have any, true, I'm a Monster fan myself and it's quite annoying, MO devotion is basically the worst Devotion.
SC has plenty of Tall punishment too, destroy units for tribute, Poisen etc etc.
The problem is not GS that's the point, SK is OP right now but not because of GS, here's the thing: Pre-Expanstion, Second wind GS was pretty strong, the deck was basically turn Swing, most of your cards were weak, and you would usually end up 30-40 points down by the end of the round, but with Wildboar-GS-Dagur-Morkvag Combo as last say, you could win being up to 5-15 points ahead, but, this weird interaction happend imo because how OP Second wind was as a leader, aswell as Wildboar-Morkvag Crazy Synergy with GSs and Dagur, but the rest of the cards of SK, outside this package, were and are trash, that balanced it out, for example Dimun Longship, 5 for 5, pretty bad, Corsair, 5 for 5, up to 9-10 over the round if left alive which usually didn't happen, still not good, and so on, that's why you were down 30-40 points when you basically played 8-9 cards that you had, but after expansion, SK got pretty Strong cards that Supports this Deck, so that Weakness is gone, with the new cards SK won't go down 30-40 Points, usually having his board wiped even, it's actually strong now and can win even without the turn Swing, but the Turn Swing is still there too, and that's what makes it OP, and the Problem, imo, is Second wind, this leader is basically *Play Wild boar or Morkvag*, how valuable is that compared to other leaders? New cards are Strong, but not OP imo, just Strong and T1, their combination with the previously Strong aspects of this deck makes them OP, play this deck with Reckless Flurry or Blaze of Glory and you'll see it's not busted without Second Wind.