The real question is what is the percentage of early Model 3 vehicles having problems? There were "nightmare" stories with the first Roadster, but only 2500 total cars were produced. Early S owners had "nightmare" stories, certainly plenty of "nightmare" stories with early Model X owners. There is a far larger volume of early Model 3 owners, however is the percentage of "nightmare" stories any higher? My guess is no.
Is the concern really nightmare stories? Or just pain in the arse stories?
Sure nightmare stories are bad, and there were some pretty bad nightmare stories from the X due to it being overly complicated.
But, I think the biggest nightmare story for the Model 3 is at the factory, and at the reported number of cars that have to be reworked there. So it really puts into question the production numbers if so many of them have to be reworked.
Most buyers are hidden from the Model 3's nightmare story except for the repairs. That's a separate nightmare story that impacts every Tesla vehicle.
The practice of refusing a delivery and getting a new VIN is pretty well known/reported so it has to be happening on percentage or 2 of vehicles ordered. There are numerous reports of those on TMC. I wouldn't call that a nightmare story, but a "why did you put me through this?" story.
It's hard to get a good count because a lot of people are accepting things that would be hard failures on other cars. In my own experience with the Model 3 if it was any other car company (Porsche, Audi, MB, etc) I would have taken one look at the bumper alignment issue, and walked right off the lot. But, I ended up accepting it and simply have a due bill for them to fix it later. So I won't show up on the list of rejected VIN's even though I should have rejected it as it was a hard failure.
I looked a bunch of other Model 3's on the lot and they didn't have the same alignment issue. Alignment wise they looked pretty good so I think Tesla has mostly solved that problem. But, most seemed to have some paint issues of some kind.
I'm not sure the average Model 3 buyer is expecting the level of perfection that you normally get with a $60K+ car. Maybe the reason I say something is a hard failure is because I'm used to Audi's, and Porsche's. So that's what I'm using to measure it against.
So it won't really show up until those like me jump ship to Audi/Porsche whenever their supercharger like network becomes a viable alternative.
My biggest concern now is Tesla is manufacturing customers for competitors. In the same way Nissan, GM made customers for Tesla by producing EV's that were good, but not quite what someone wanted.
If I was Sales/Service of Tesla I would really focus on improving the delivery experience. It's the easiest part to fix, and has the biggest return on investment in terms of customer loyalty.
With cars the customer loyalty aspect is huge. Most buyers like myself simply go back to what they know/trust. Why did a buy another Tesla? Because I had a good experience with my Model S.