You know who I mean. We've all had to work with (or around) the guy everyone calls the pain in the ass.
He is not the person you would choose to make the decision, but he is a person you definitely want in the room when the options are being explored.
He has insights and ideas that are missed by many, including (or perhaps especially) by the experts and authorities. He has unnerving idiosyncrasies in his world view and big gaps that attend execution. His approach to organizational political processes can damage acceptability and derail execution. He can be relied on to offer alternative perspectives to almost anything. He tends to be perceptive - and is occasionally brilliant. He does not suffer fools gladly although he often tries to do so. He has an irritating belief that his perspective is so compelling in its clarity and validity that it needs no explanation. His intensity and work ethic intimidate others. Over time, his wit invariably produces an impressive cadre of enemies, some of whom are not in his league when it comes to creativity and analysis, and many of whom will no longer entertain any idea he supports, let alone suggests.
When discussing major decisions, ignore the grumbling of others and your own misgivings. Make sure he is in the room.