I suppose I was ambiguous about whether I meant westernization or regencies. Apologies, I meant regencies, since they were brought up.
You asked for a coherent argument on why such pauses in the game are bad, and I gave one: having zero or one degree of freedom makes for boring gameplay, because there is no game. When df is zero or one, there is no choice, and hence there is no strategy. Since EU4 does not have a motor component to supplement the decision making/strategic aspect of the game, that implies for the period where df is zero or one, there is effectively no game to be played. To say that a game is bad during periods where it ceases to have any game elements seems both coherent and uncontroversial.
I think the picture is more complex for westernization, especially under the new rules, but it holds completely for regencies. It makes no difference how accurately it simulates something historical if it makes no gameplay sense, much like it doesn't matter how much gameplay sense something makes if it's ahistorical nonsense.