I found the exercise pretty helpful. At first, I was looking at the poem on a surface level and looking at the exercise on a surface level. But as we started shuffling the words that the poem had I realized that I was noticing aspects of form that I hadn’t before. Rhythm is preserved if it’s done right and the Mad Libs reveal what kind of words are not included in the original poem. Poets are often hyper aware of form and rhythm so to note these things is important. It can preserve the “mass”(number/kind of words) of a poem while reforming the words around a base “skeleton”(form).
I would love to do this with “Do not go gentle into that Goodnight”, partially because I think it’s great comedy fodder. I think longer or extremely short poems have a better chance of accidentally forming coherent ideas. I don’t think that finding “meaning” in the mad libs isn’t the point but I would be fun and interesting see what ideas come up from the word shuffle.
I think one of the limiting factors of mad libs falls into trying to force meaning on the nonsense that you can create. It’s really fun to laugh at what comes up but getting too hung up on “the meaning” tends to hold us back from noticing what we find as we peel back the words of the poem.