Problem 1: So, the 787 line is booked out to infinity. Invariably, a portion of those orders will be posted to the used aircraft market and sold with ridiculous markup. Now this wouldn't be a problem on an aircraft that has minimal demand and production slots can easily be acquired, but on the big selling aircraft this deprives other airlines of production slots.
Problem 2: Alliances unfairly get a jump on aircraft now. As a solitary airline who thinks alliances are dumb, I'm limited to receiving 1 787 a month. However, airlines in alliances have other members buy aircraft and take up production slots, meaning they can take on 2 or 3 or 4 787's in the same period. In the real world, new aircraft are delivered with limitations on resell. Ryanair was a notable example of this, as Boeing did not want them unloading new build 737-800's onto the used market, undervaluing the price of a new one bought directly from Boeing.
So, the premise is to add a limitation on a newly purchased aircraft in how quickly they can be resold. Perhaps an airline has to wait a year, maybe two years. This would be reflective of reality, and balance the playing field from the favor of the aged and anti-competitive alliances to all players. Furthermore, this would result in more equitable production slot allocation.