So what? There are many troops without poison that cannot kill beside skulls. Just choose troops that make sense together, that’s true to any team in the game.
Considering how long it would take to kill someone with the sole use of poison with most troops at 25+ life, I dont see a big problem there. A game usually doesnt take 25 turns to finish with the insane skull damage nowadays.
Think early game. The troops have 9 or so health and you cant get a skull match or the enemy has high armour and gaining more. We have troops that can alter the board. He have many troops that can do damage or buff themselves. We have no skills that kill on the opponents turn but we have troops that can ignore armour or kill multiple troops at a time.