Sacrosanct
Legend
That makes it seem like 3 would be the last of the introductory levels then. However
That is much better evidence.
I wasn't around for the playtest, but I'm willing to take you word on it.
Well, I was there for the whole playtest as well (and still have all of the versions) Levels 1 and 2 were not designed specifically as introductory levels. Again, because they were part of the introductory phase does not mean they were designed specifically for to be introductory levels. We know this for several reasons:
1. They came right out and said they were designed for the playstyle of gamers who preferred a more zero to hero game
2. If they were meant specifically to be introductory, that means by inference that once you became familiar with the game, you wouldn't use them any longer, which is obviously false because many of established experienced gamers still do and prefer to do so
3. WoTC has put out an official introductory product. One that was meant to be introductory. It has PCs that go up to level 5. Not 3. If any selection of levels was meant to be introductory, then obviously it's levels 1-5, not 1-3, because the actual product has it that way, and not some random person's arbitrary interpretation based on when subclasses appear, which leads to...
4. Some subclasses are gained at level 2, so obviously level 3 isn't the magical level where introductory levels stop if that's your metric.
However, and it bears repeating, that just because levels 1-5 were in the official introductory product, does not mean that that levels 1-5 were specifically designed to be introductory. Those are two different things. No level was meant to be introductory as it's primary design goal, not only because they said that wasn't the reason, but because they are meant to still be played regardless of your experience playing the game.