I think you and the GP are actually saying the same things. Where GP says OOP requires you to "create upfront the separation of concerns, before code has had a

I think you and the GP are actually saying the same things. Where GP says OOP requires you to "create upfront the separation of concerns, before code has had a chance to run...", you refer to allowing "a developer to _freely_ express their concepts" (emphasis mine). I think that "freely" is what GP is complaining about; that OOP practices limit your freedom by encouraging early lock-in and making past decisions hard to revisit in light of new facts. I'm not sure I entirely agree, mind you, but I do think you're in more agreement than disagreement.