Btwwl, wouldn't it be Louie who would be the 'dropped on the head' instead of Dewey? I mean, it makes sense that it's Dewey but it's Louie who's always made out as the negative one.
I was very much expecting that joke to be at Louie's expense. Choosing Dewey made no sense to me.
Originally, yeah, I'd say the normal butt of the joke would be Louie (he was dubbed the 'evil twin' at the start) but since they made Louie the next gen master planner, schemer, big picture guy in the season premiere ep, I think they had to go with Dewey as the 'dumb' one now. And Dewey has now been pegged to jump into danger without thinking and all that.