IMHO, the level of difficulty is not really based on Disney's Bell Services doing their job - generally speaking there aren't many problems, and considering how many people are checking in and out of WDW every day, there don't seem to be too many people switching resorts and complaining.
No, the real level of difficulty is you and your party, how quick and easy will it be for you to pack in the middle of your trip to move to a different room?
My wife and I did it once, and there were no troubles, but it was just the two of us. Next time we anticipate going, it will be with a pre-schooler and an infant or toddler, so I can't imagine willingly switching rooms mid-trip until they were old enough to do their own packing, if at all.
But when we did it, I was glad we did it. A week in a studio at the Wilderness Villas. followed by 3 nights in a 1BR at Boardwalk, giving us an opportunity to stay at a MK resort and an Epcot resort, AND to get all our laundry done before leaving for home, so we could pack less or not spend an afternoon in the laundry room of either resort.