Cleanliness is a big thing. I am always impressed by how clean the park (the restrooms in particular!) is, considering how many guests are there daily. Speaking of guests, seriously people, there are trash cans like every 20 feet. Do you have to toss your napkin/popcorn/wrapper ON THE GROUND?
Yeah, fix things that break - promptly.
Give the CMs decent pay and benefits, hire those who really want to work for DL, and give them a bit of leeway in their jobs. I kinda miss the CMs on Tower who tried to outdo each other in how creepy they could be.
Encourage CMs to gently enforce some kind of courteous behavior among the guests. Break up the giant groups that stop in the middle of Adventureland to visit or plan; make a joke while encouraging the aforementioned guest to use the trash instead of the ground; put a stop to the adolescents and teens who seem to think running and pushing people out of their way is somehow ok.
A stroller policy! I have been an AP holder for over 10 years, and the proliferation of strollers (in number and size) is shocking. Does your 8 or 9-year-old really need a stroller? And do you really need to bring the Supreme Deluxe Extra Huge model with room for all your luggage for a 10-day trip? Ever been hit on the back of the calf by one of those? We have. Often. And keep them all out of the locker area. Please.