It stand by my reasoning for the last few years that we have reason to believe WDW will be up to par by 2021. Let's all remember Disneyland prior to 2005. It was essentially where WDW is today. California Adventure was still mostly new and shiny, but far from perfect, Disneyland was feeling neglected, etc. 2005 and DIsneyland's 50th brought a complete resurgence to that area at the time when WDW was on its downward slide (after a strong 90's resurgence). So, here we are 10 years later and approaching MK's 50th. And, indicators are that (maybe Epcot aside) the place looks to be in great shape by then. Expanded AK with nighttime show and activities, Complete redo of DHS (whatever it's called by then), a brand new shopping and entertainment district (with ample parking!)...
I feel that most things will be in place by that 2021 celebration. Hopefully I don't have to wait until 2032 to feel that way about Epcot specifically.