Although this organizing pattern is more complicated than the others, it offers a proven structure that can help you organize your supporting materials and achieve your speech goals.
I have never heard of the Monroe's motivated sequence. After reading about it I actually like it. I think that it is important to have a plan or a layout so you know exactly what you want to do. I like that in this sequence you don't get to the problem until after you have grabbed the audience and establish the importances of the speech. I like that you leave the audience with how can we fix this problem.