Better than Uber?
With the 30 minute wait, it might appear to be slower. But, it might be the same or faster since you skip not only the security gate, but everything leading up to the front gate: crowds, huge parking lot, slow ferries, monorail transfers, full buses, etc.... You wind up close to a back door gate and, bam, you're now deep into the park.
Also, Uber doesn't show up immediately. And you pay for both. Do you want to pay Uber or pay Disney? Yeah, I know you want Disney to give this to you for free, but... that ain't happening... unless they increase the Hopper price and make it part of the Hopper upcharge.
What's unknown if each bus (or van) is directly going back and forth between each park, or, if they're on a loop. If they're looping, you may have one to three stops to get to your destination. We'll see.
Ruin the Backstage Magic?
No, you're not getting a tour of the backstage, although, you could pay for a backstage tour if you want. You get dropped off near a employee entrance with all the charm and magic of an employee parking lot. So, leave the soul of our dearly departed, Walt, out of this.
All the people rushing to use it will upset... stuff!
Really? Just how many people get the Hopper upcharge to begin with? And even if they have it, how many actually hop? And if they are hopping, how many hop more than once per day?
I know for me that if I planned to hit three parks or had a tight schedule with two parks, I might buy this. But, if I'm only going from one park (one of the so-called 'half day' parks) to another and didn't have a tight schedule... then I certainly wouldn't use this.
This is for a very small set of multiple-hopping hoppers. And it's probably to convince them to spend part of the day out of the crowded MK by making it convenient to do so.