The Internet is the worst thing ever to happen to the Disney fan community. Sure, it brought thousands of people together, but it also led to a ridiculously skewed perspective.
Twenty years ago, I guarantee the engineers and ride developers went through the same machinations regarding technology and practicality, making hundreds of changes -- most minor, some major -- to nearly ever proposed attraction. Except in those days, we weren't privy to every minute alteration and judged the attraction after completion.
There is no reason to believe that this ride will not be built as originally planned. Is it possible that Disney is having trouble with the swinging mine carts? Absolutely, I can buy that. But to take that nugget of information and conclude it will lead to the attraction's demise is nothing but ridiculous hyperbole. This is entire situation is nothing new, nothing strange, nothing unusual. It's just the typical bumps and setbacks in the production of a new Disney attraction.