There were several COAs evaluated. However, prior to FM 5-0's current draft there was an FMI on design. The way ahead after the release of FM 5-0, FM 6-0, and the design FMI was to incorporate design into a future version of 5-0 (primarily) and 6-0 (when appropriate). However, the ongoing doctrine reengineering effort aim to cut down on the overall number of manuals and redundancy between manuals; thus, it was decided that design would doctrinally be covered in this iteration of 5-0 and the FMI was dropped. As I mentioned in a previous post, some of the decisions on design have been temporarly deferred. When I hear something concrete, I will post it here. I hope that helps.