Gallagher needs to better manage his energy to be able to contribute more offensively. I feel that lately, he's been wasting way too much energy on after whistle scrums instead of using it to actually play hockey. Constantly initiating and shoving against much taller and at least 40 pounds heavier opponents after the whistle is draining.
I'm ok with him showing some fight when he gets hit or pushed after the whistle, but sometimes he provokes it when it's really unnecessary. He goes way overboard with it or spends too much times going back and forth, when it could just be stopped. He's not hurting anyone but himself in a prolonged scrum.
One of his bread and butter for scoring goals is being quicker than opponents, jumping on rebounds around the net. He's not even a slow skater, it's just that he's gassed out only after a few strides when he gets on the ice so he is no where as quick and effective offensively. He doesn't have an amazing shot, but his release is quick and deceptive enough to beat goalies from time to time. The problem again is that more often than not, he doesn't have anything left in the tank when he makes those shots. Obviously can't have much accuracy and strength in your shot when you're drained.