I'm not a Canon shooter but the 70-300 doesn't seem sizewise to be a very big lens compared to the 70-200 f2.8. I would carry it because as some have said you will need it for AK, but also I have found the foot zoom isn't always an option, AKA, the shows in front of the castle. I have also used the extended reach at Epcot when shooting across the bay for some of my night photography. At some of the auditorium type shows you may also need the extra reach. Do I like wider, yes, sometimes. When at WDW, I primarily carry the 18-55 (kit), 28-70 f2.8 (walkaround) and the 70-200 f2.8. Eventually, I need to add the 30 f1.4 for the dark rides.