Im sure they are basing the idea of the queue size on the number of bus riders at park close for the resorts on the line. For all the crus that comes out of Epcot and the Studios, the bus lines aren't that long now...they just build due to a batch system and then get eaten in chunks as busses arrive and dispatch.
###WARNING...SOME ASSUMPTIONS ARE MADE HERE, BUT THEY DO PAN OUT BASED ON HISTORICAL PATTERNS###
For a continuous load system like the gondolas, there isn't really a need for a large and winding maze. I made a rough estimate on the number of rooms at CBR, based on the estimated speed of the gondola and the expected average capacity of similar systems in use across the globe and was amazed that you could load almost the entirety of CBR guests (assuming 90% occupancy and 3 per room) within an hour. We know that's not a realistic scenario...there will be significant numbers of guests at the other parks, not at any park or whatever. A more realistic estimate would be about 15%-20% of the people at CBR (or any of the gondola hotels, actually) would be at Epcot on any given day...It would most likely be able to chew through that entire group for all the hotels on the line within 45 minutes, assuming everybody instantly rushes for the gondola and arrives at the same time. The natural spacing of people and their distribution in the park will serve as a strange virtual line in its own way...people watching the new evening show near Mexico will likely not even arrive at the line until well after those watching near the UK, etc...
I would guess the maximum queue they will need for the current system would only need to account for about 10-15 minutes worth of wait, just because people get there fast, some linger after hours, some leave early, etc...