I'm sure that this has all been considered (and perhaps already written into the FP+ computer code). Like the ability to hop between parks and additional FP+ choices being made available after the first 3 are used. That upcoming change was announced a couple of days ago. Who knows what else they've got programmed into the process, but have not turned on? It might be that they begin to offer additional tier #1 FP+ as an addon to your tickets. For a fee, of course.
However, I just don't see Disney going back to the old ABCDE-ticket ride format. It doesn't account for entertainment costs that guests enjoy as a part of their admission now. In fact, most amusement parks no longer use a tickets-per-ride system. Most have single-price admission with tiers for shorter customers and discounts for seniors who tend to skip the thrill rides.
True
However back then cost may have been the factor. You had to pay someone to sell the tickets and you had several booths thruout the park. Ticket stock cost money. With either system you still need someone at the ride entrance. With a magic band they don't have to retrieve a ticket. Just watch as you scan the band. Also they had to determine if you had the right ticket. The band takes care of that. It could be done but profitability would determine that.