Hmm. Interesting game.
I'm not sure I agree that the bridge crew is mostly interchangeable, even if that was supposed to be the idea. I'm trying to imagine Riker as counselor or CMO and it's not a pretty picture. He would make a great security chief, though.
Picard would've made a great science officer. In fact, when Q offers him an alternate future as opposed to death in Tapestry
, that's what he's shown as becoming (though he's not happy about it).
Beverly would've been a great captain, and the few episodes where she ends up in command of the Enterprise or of a mission show this.
I struggle to see Geordi in anything other than an engineering or science position. Maybe CMO, if he had an interest in medicine instead of engines.
Troi was useless, so I can't see her as anything.
Data is maybe the only one who really could be excellent in any position. I even see him as being a great counselor (certainly better than Troi). His perspectives always shed more light on the behaviors of those around him than anyone else's. It's fairly obvious that he'd be great at everything else.