As for the second point about variable ticket prices can't see that working. Not if the top end is as high as say US$25, the question is what price is the consumer willing to pay. Do they say want to pay US$25 to see it once or wait until it comes out on Blu-ray and pay a similiar amount to see it any time they want.
I think you'd find that the market would have a high tolerance for paying more to see big budget films. Especially if this paradigm also delayed release of the films on physical media, or if prices of disks were tied to budgets.
I think far more likely, though, will be the emergence of boutique theaters. People will pay more to sit in a nice theater with leather seats, dinner, drinks, etc... A place where "no cell phones" is actually enforced, and where you can get an experience unparalleled from home. I have a 124" projector screen in my living room, so I only go to the theater to see films that are truly worth the theatrical experience these days. Everything else can wait for BD, where I can pause my movie to go refill my wine/beer or flip over my steak on the grill.