Morton stands to upright when he's kicking for goal, which lends itself to leaning back on impact which causes him to spray it a fair bit, also if you watch someone like Fev or Aker they hold the ball still and over their kicking leg. Morton needs to take his eyes off the goals and focus on the ball drop more, his snapping for goal is great but is only effective from the one pocket.
Overall the team lacks poise when it's time to capitalize on the momentum, I think that's what Cousins would have been drilling into them at half time.