I was also thinking that some of the changes from package to package might also be changing switches/dials to see how different settings play. Is that right? Even plausible?
I personally have always taken this as a given.
One packet has an alignment restriction for the paladin, another one does not. Do we (or WotC) know which one will be in the basic rules? Not until they release both options and hear from the masses what their preferences are.
One packet has true Vancian casting (select your spells in the morning slot for slot), another one has pseudo-Vancian casting (select your spells you prepare in the morning, but cast any number of them in any slot you choose). Do we (or WotC) know what which one will be in the basic rules? Not until they offer both options and hear from the masses which form they prefer.
One packet has a Short Rest of 5 minutes, another one has it as an hour. Do we know which one will be the basic rule (with the modularity to change it to other times as each game desires?) Again, not until they hear from the masses what they prefer as the basic rule.
Then, once they get a baseline for all these basic rules... the ones that are predominantly popular with the gaming populace... they can use the other options as modules for the basic rule. This has seemed to be their modus operandi from the very beginning, and why I've never really understood the doomsaying from people thinking that the game was moving away from the D&D they want to have. Because it has seemed like every packet has moved closer and further back and forth, as all the different options and dials get put out for us to rail against.
They've been doing their job by offering all the options for us to support or rail against... and we've been doing our job by actually doing so.