I really dislike this idea. Every time one of these little money making schemes comes out it makes me less and less excited for my next trip. Having a two-tier transportation system just doesn't feel right. If it works, they will reallocate more buses and drivers to the paid system from the complementary system (or rather, the system that we are already paying for in our tickets and room rates). If it doesn't work, then they'll probably do the same to make the paid system look more attractive. Or at least, that's what the perception will be when you're waiting in long lines for the complementary buses - it will make people feel like they were losing out because Disney thought they were being too cheap, even after paying thousands of dollars for their vacations.
Also, guests shouldn't routinely go backstage (unless on a backstage tour). Whatever happened to Disney's focus on 'show'?
I pay enough for a Disney vacation. Transatlantic flights, hotels, tickets, food, drinks, events, merchandise, tips. I don't like the idea of paying all that cash and then constantly feeling like I'm losing out and having a second-tier experience unless I pay twice for everything. All of Disney's latest "initiatives" just make the experience a little less magical for me. Others disagree, of course, but that's how I feel.
I mentioned this to my family and their first reaction wasn't "oh we'll pay for that" but rather "maybe we should just rent a car next time then". And if we're renting a car, then you can bet we're going to check out WWOHP.