Since the Barrelmancy is a holdover from DOS2, it is unlikely to lose effectiveness over time. At the best, you'll need more barrels to instakill everything, but it wouldn't be hard to achieve that. Ultimately, if they wants barrels to stay, for the health of the game it would need to be toned back A LOT. Have a lot less barrels, make it not do as much damage, and make them super heavy. By making them more rare you still could solve a hard encounter with it, but that'd be a product of saving resources and planning so it'd become actual; strategy and not a cheese to take care of everything. And by lowering the damage it'd become just a good first turn and not the instawin button it surely would be.
