I'm not actually sure I agree here, I think this is game design all the way down. The problem is that the gameplay loop, the point of interactions players are "supposed" to have with the game is generally insufficiently ambitious, or too generalized. The game design task does not end with making an encounter last approximately Y rounds and drain Z resources. If anything, that's what's been reified; the baseline evaluation of how encounters work has gone from a tool to guide the secondary encounter design task to a target.
I think that's what drives the overreaction to "balanced encounters are fundamentally a mistake" or "we need to simplify enough I can use HD directly." The problem we're actually dealing with, "how do I know what players can overcome?" is a much harder question, and we keep answering simplified versions of it instead of grappling with it directly.