HI all - here are my experiences with upgrades and room changes: hope this helps. Over the years we have been able to upgrade about 35% of the time.
my definition of the upgrade includes room view/location, room size, and or amenities (like club room, tickets, FP options).
- be prepared for the answer "sorry none available"
- be polite - you get more with sugar and honey than with an attitude
- be flexible, consider asking that after you check in - if an upgrade becomes available that you would consider moving the next day
- rooms are assigned between 1-4 days before you show up. Each Disney hotel has a room assigner - consider calling ahead of time during the 1-4 days and asking for upgrades. If they say there is one, they may ask for you to pay the difference/or they may not. Be prepared to answer.
- you can ask for the upgrade at the time of check-in; don't hesitate in asking.
- consider booking at two hotels during your stay - split up your vacation. We never thought of doing this; one time a Disney travel assistant suggested this - and I am glad we did. We booked 2 nights at the Poly and then moved to 2 nights at the yacht club. The transition is easy (they move your stuff) and upon reaching the Yacht - we asked for an upgrade and received a larger room.
- Here is a long shot idea with large groups - came to us when we had a family reunion at Disney. If you get a group to stay in 10 rooms or more at Disney, they assign a concierge-type person for you and the group. you get up to a 20% discount and they handle room assignments and extras. you don't have to stay in the same hotel - they will get you 10 rooms anywhere - we did this with a family trip in 2016. in doing so we had family at the boardwalk, yacht club, springs, contemporary, Carribean, etc... and half the families received room upgrades at a discount. We never knew they did this - it was at the suggestion of a Disney travel person FYI. They even coordinated family shirts for the occasion.
Good luck - hope this helps!