Uh, I wouldn't really use it as indicative as anything.

Learning to be competent in this game, to a certain extent is on the player, e.g., it gives text descriptions on buffs/debuffs, you get descriptions on abilities as well, etc., - It does not care whether or not you are competent because it is story mode content, and it is developed in a way that it can be completely by anyone, that is the point.

Getting to level 50 quickly or not, and without interacting a great deal with side-quests etc., I wouldn't really see it as having any bearing on retention, given how many expansions people need to get across, really. If the base game only included base ARR then I'd be inclined to agree - But they need to account for the fact it just isn't ARR. Sure, it would have greater longevity, but at what cost? How many people would quit? What does a profusely long leveling process offer? The repeatability and retention come from the content types, not just how long it takes to level.

On the note of the rain - It's actually interesting you bring this up because on the other hand forcing a weather change for a cutscene would be considered equally as clunky, even if it doesn't raise the same questions, which it might. "Why has the rain just suddenly stopped as soon as I went for pancakes" - Children have an absurd inquisitive nature about the world and its workings, even in general... Until education puts people through the treadmill assembly line.