It's specifically there so that you are deciding which way you want to go with regards to AP rather than having a built in combo. There are many runes, but different ones, that you want to use with it depending on which direction you want to go.
- Yeah just doesn't feel good considering his drawback only second upgrade line and punish being specific synergy to cull... I mean what 2 distinct "different" directions am I going with punish over cull? Anyway no biggy...just would make this guy playable in the deck I feel he "looks" designed for if he had dragonflight swapped with punish, you don't even benefit from the synergy without 8 AP anyway.
