There's LOTS to do in the World Showcase! Below is a sample itinerary I made for our upcoming trip; this is on a Wednesday in April, and has the exact show times of each of these performers in their pavilions. Keep in mind, I have
Mo'Rockin

on another date we will be there! Each of these below are considered 'not miss' shows! I got the show times and the list of performers at Steve's site. Hope this helps you a little!
Time Pavilion Act/Group
11:30 England World Showcase Players
12:55 Japan Miyuki - Candy Maker
1:35 France Chair Act
2:00 England British Invasion
2:30 Canada Off Kilter
3:30 Japan Matsuriza - Drums
4:15 American Voices of Liberty
4:30 American Fife & Drum

4:45 American American Vybe
5:00 Italy Living Statue
6:15 China Dragon Legend Acrobats