See California Adventure and its 2.0 overlay and the impact it had on DL's daily traffic patterns.
Give people a reason to not stand in the Hub each night watching Wishes or a color changing castle. That will prevent the need for mass exodus and the bottleneck on Main Street. Keeping the other parks open longer and giving people reasons to stay all day are the only way to help MK.
The solution to MK's issues can't be found internally unless you want to continue to slice more and more space out of the equation to either cram more people in or bypass people out.
The only solution is to give them a reason to not all be there to begin with. They have 3 other parks. Fill them and then you can get back to the business of upping MK's gate. Adding more reasons to be inside the MK only compounds its problems and the overall problems plaguing the rest of the parks.
NFL made things worse. Not better.
The real issue is that TDO doesn't care because a gate spinning somewhere is still money in their pocket. Who cares of if quality suffers (refurbs cut short or underfunded, Hub refurbs that have taken more than a year, and yes... the evil light towers).
Pandora, Star Wars Land, Pixar, Frozen will help... but, much more is needed. A Universal effort is required with years of things in the queue for the other 3 parks before the problems with MK will be eased.