In Imperial Assault skirmish, they added this rule after it was clear that having more activations than your opponent was a huge advantage:
“During a skirmish, if a player has fewer ready Deployment cards than his opponent, that player may choose not to activate a group and pass play back to his opponent.”
After implementing this rule, activation advantage became much less of a thing.
In Legion, activation advantage is still a huge factor and every time it comes up in a game I wonder why there isn't just a pass rule...
"On his turn, if a player has fewer un-activated units than his opponent, that player may choose to not activate a unit and pass play back to his opponent."
How would that not improve the game?