actually... here are my thoughts on this
Disney is starting to lose some people to other parks in the Orlando area... meaning when people go to "Disney" they are ALSO taking a day or 3 and going to Uni, SeaWorld, etc. ... Disney wants to keep everyone on property... this is obvious... so in order to do that, they need more to do and/or an incentive to stay (I know that sounds weird but hear me out)
What Disney needs to do is have a major refurb at EPCOT with some new attractions in place of Energy, JII, Soarin' update, maybe even a new ride in a county then move onto DHS where well, you know it needs a complete overhaul.... then DAK needs a new "land" and a few new must sees.
Once complete look into a 5th gate.
Each park needs to have at least one of the "oh I have to go see that" attractions...overhaul like Star Wars/Carsland at DHS would do that... Avartarland (not sure) or a World of Color type show would at DAK, EPCOT just needs a few updates of old attractions, and then we also can't leave out Disney Springs now that might be a full day adventure for some people once it's complete
So look at it this way as a possibility:
Magic Kingdom (1-2 days)
EPCOT (1 day)
DHS (1 day)
DAK (1 day)
Disney Springs (1 day?)
5th gate (1 day)
Total: 7 days
Waterparks are an optional 1 day (but with an extra ticket expense I didn't include that
then Disney needs to look at incentives to keep people on property... I'm not sure what to do here... but think about offering 1 free counter service meal per day per person (when staying on property) at each of the 5 parks/locations.
Ex. 1 day at MK, 1 day at EPCOT, 1 day at DHS, 1 day at DAK, 1 day at Disney Springs (could even throw in the water park to get people to do that as well).