you could easily flip that around though. If players only ever do ST rotations then they'll "get bad" at AoE. Dungeons are there for you to apply your skills, not learn them.
And people didn't call nerfs on PS for hard trash, they called nerfs on the bosses. People were fine with the trash, and that's the only real example.
You have an idea of "play correctly" that is more of a personal preference. Which is fine, until you start telling other people they're wrong because of it.