I do understand what you meant there, Engines, but Air Staff do tend to get selected for their "personal operational experience". Not so much now as folk get matched up to a vacant post because they are due a posting. Maybe a few round pegs in square holes? And they could be even worse than people with "personal operational experience" of the systems in question.
I'm not sure if this is a doctrine I subscribe to, but there is also a line of argument that states that we sometimes over-define and over-question our requirements. And then do more thinking and change stuff. There are some good guns available out there and unless the UK decides to put a lot of money into developing new ones, This argument might suggest you just buy the one that suits your needs. The effectiveness of most of them is, after all, quite well known by now. It's debatable.
I'm a gun fan, for many of the reasons already discussed here. Shame we haven't done more with them. I guess it's a shrinking market for expensive R&D these days.