The only issue I see with this is that the monster deck can do it with the starter deck, other factions really struggle to answer it until they've unlocked some more cards. Maybe they can change the starting monster leader or something so it's less oppressive for new players without changing overall game balance.
Even if annoying, the fact that makes this strategy effective is because the opponent passes the round. If you see the combo, try to beat it with strength. The people who use this technique play Eredin first (to avoid having geralt being silver by the counter), then Geralt, then pass. However, as the opponent, if you keep playing and they pass, you can beat the round and have a round in your hand, all the opponent's large strength drained AND no leader ability for them to use. Sure, you ll start with card disantage and your opponent will have 10-12, but using the leader ability when needed and not at start is a huge plus and you can easily win in later game especially if you have a few removals (ideally a scorch and a lacerate).