Here's a brief synopsis of what went down.
Chapek comes in, replacing Staggs. Chapek knows nothing about theme parks, takes some time to try and get to know the business unit (despite what some people think of him, he has made legitimate effort to understand his domain unlike say COUGH Jay I-Hate-Theme-Parks Rasulo). Once he rolled around to reviewing projects in WDI's pipeline, he had a very valid question for everyone - why have they been sitting on the hugely popular Marvel Cinematic Universe? Disney has owned Marvel since 2009 and despite some close calls, no major attractions had been greenlit.
It did not make sense to Chapek that WDPR had been so slow to capitalize on Marvel. Coming from merch, he understands the big brands so he emphasizes IP-based attractions.
So Chapek asks for proposals - quick ones - to get some Marvel breathed into the resorts where it can be added (DLR in particular). GOTG TOT was drawn up some time mid-last year very quickly, as part of Chapek's directive was to make use of existing infrastructure where possible. This attraction was very much a rush job that stunned everyone when it was approved, and yes, Chapek wanted it in WDW too (this has since changed and will hopefully stay that way).
So compared to the average attraction design and build time, GOTG was definitely rushed. That does not mean the end product won't be good - in fact, I'm positive the ride will be a blast. The exterior I'm not sold on.
Chapek was also amazed and flabbergasted that WDI was allowed to be so reckless with budgets; spending whatever they pleased and taking forever to do anything. He wisely removed Vaughn, who was the worst, and Weis is a far better leader. WDI needs to be more nimble than they had become, so his organizational changes there were good ones.