John Brebeuf
First Post
If you’d read the whole post, I talked about strain, and then wrapped up challenging the notion that there is any appreciable difference between two things.
I did read the entire post, and you didn't talk about strain at all except your own experience of "burnout," which is irrelevant to the post you were responding to with your question and the question itself.
As to what's an "appreciable difference," a DM is called "Master" for a reason: he has to have at least as much mastery of how a class works as any of his players, and that requires more than a mere glance at a few pages. He has to think about how it would interact with the elements already incorporated in his campaign and make a considered judgment as to whether it would benefit or hinder the course of gameplay. That involves, to say the very least, an increase in cognitive load.