I was just watching the commentary for Superman: Doomsday, and Timm regularly says something like this- “I had this crazy idea to have Jimmy constantly chew gum during the movie. In the final Battle Superman would use it to stick the Kryptonite on the clone. Thankfully Dwayne [McDuffie] talked me out of this.”
I then realized he said many similar things in his other commentaries. It does show that he needs somebody on staff like McDuffie, James Tucker, Richard Fogel, or Paul Dini to keep his wackier ideas in check.