What about the man/woman?
I've read through most of this thread and seen a lot of informed comment, but the salient point should be not about organising around weapon systems, they change - we need to think terms of interoperable teams.
If. as was stated earlier the ideal base team is 4-5 then organise around that, build up your structurre from the base. When it comes to weapon systems, design them around your teams and the tasks that you have them perform. You have to be able to operate in a variety of theatres, but your recognition as to what is required for weaponry is driven by the task that people are expected to perform.
It will never be perfect, because the enemy will not do what you want them to do - it is not in their best interests, so we need to focus on well trained people who can react to a changing situation and sieze the initiative and thus dictate the pace and tempo of the battlefield around them.