First line of the OP.. this is not about 30 vs 60. I know there's a difference, I can see it too. And I know that 60fps is better. That's not the topic. I get the impression you're mainly a PC gamer.. this is primarily a console discussion, since there really isn't any such thing as a 30fps PC game these days (nothing that Durante can't fix, at any rate).
Let me ask you this, to try to clarify my point: As a console developer targeting 30fps, do you think it would be beneficial to pare back on visuals in order to hit a 100% locked 30fps, or go for the shinies and spend most of your time south of 30?