This is a balanced response but I must make one semi-contrary point ... that there are enough facts and circumstantial evidence to support the assertion that A) MM+ is behind schedule, B) MM+ is overbudget, and C) spending has been reduced from other areas subsequently.
Here's the facts:
A) Staggs, Iger, and official Parks Blog indicated in January of 2013 that it will be rolled out in the next couple of months, at one point Iger said in an interview that Summer of 2013 was the plan ... it's now 2014 it's not rolled out completely. THE RESULT: Behind schedule
B) Due to the project being behind schedule (in addition to the technical issues it's faced) it's a cause and effect thing ... the project HAS to be over budget if it's this far behind schedule. We don't need an insider to tell us it's over budget, we can see it is.
C) Spending has been reduced from other areas? Perhaps this takes the biggest leap of faith but not really ... we know MM+ is behind schedule therefore we know it's over budget and we KNOW nothing major has been announced since Avatar in 2011 (outside of Disney Springs). I'm not saying anything about construction or rumors, let's just deal with real facts ... so for roughly three years they have announced NOTHING.
What can we logically infer from that? That money is tight, that money is being spent elsewhere and since we know MM+ is behind schedule thus over budget we can assume that's where it is.
So to me, you don't need any insider information. Just based on what we can see and what is real you can state fairly definitively that MM+ is behind schedule, over budget, and has affected improvements/additions in the theme parks. And until something major is announced (that isn't a shopping/dining district/hotel that turns a profit relative to it's construction costs) then it'll be hard to make a counter argument.
That being said I appreciate your balanced response, I just wanted to make this point not directed at you personally or as a contrary response but ... I guess just to make it.