We're a ways away from big changes, and Kakashi isn't the type of guy to focus on excitement - he seems content with his appearance and it doesn't factor into much of anything for him. Should Sakura ask him about his appearance, he'll consider how to make himself appear 'fresh' ...but I can't see much more than a haircut at the moment. Sorry if that's boring but I don't want to feel pressured to change anything without some IC reasoning.