Although I'm against the precedent (explained below), I'll play devil's advocate. Disney could do this - the restaurants could take the firework view sections out of rotation about two hours before show time, set the reservations for about 30-45 minutes before fireworks start, and they'd sell out every table for every night in a heartbeat as soon as they were available.
Worried about the cost of shutting down that section for part of the evening? Or guests that just book the table for dessert or an appetizer? No worries - make it a package. Guests reserving a fireworks view table pay a flat rate package fee per person that not only includes the cost of dinner but also the upcharge for the premium firework view as well as the average per table revenue that the restaurant loses by closing off those tables before the event.
And that's where it gets tricky. I'm guessing the starting price on something like that would be around $250 to $300 per person. People already pay close to $100 a head for the dessert parties. Restaurant fireworks tables would come at a significant premium - very lux and very exclusive. But there'd still be high demand. It's Disney. These would be one of the hottest tickets in the kingdom (given that there are, what, maybe 100 tables that could participate each night? 150?). And while the people who score those tables wouldn't stress about getting a good view, you've just transferred that stress to thousands of people who will do everything they can to secure that package the second it opens and fret for weeks or months to find a dropped reservation.
Currently? It's luck of the draw. Like winning the lottery. Everybody's in contention - all you need is a reservation. As for the bad precedent? I like that Disney generally offers the same basic park experience to anyone who walks through the gates. Disney offers "shortcuts" and upgrades to enhance the experience or make it easier (dessert parties, tours, EMM, etc.), but it usually doesn't rope off the basic experience only to those willing to pay even more (everyone can still ride the same rides, eat in the same restaurants, see the same shows, watch the same fireworks). It might require a little more effort, waiting or luck than just forking over more money to bypass those inconveniences, but the experience is available for "free" with some perseverance. Bad precedent for Disney to monetize some the best and most magical base experiences only for those able to pay a substantial premium.