As far as recent Rangers go, John Moore and Michael Del Zotto check those boxes.
Moore was always referred to as a "all the tools but no toolbox" kind of guy, and he'd wow you with some great plays, but he'd also have some head-scratchers. He's stuck in the NHL though, so he's doing something right.
Not sure what Del Zotto's problem was. Maybe it was just being a young guy in New York. Nice to see he's carved out a career, though. Doing decently with Vancouver, and he has an A to boot.
I've had a lot of guys over the years who I thought would be stars (or at least part of the hall of very good), but they never put it together, either due to attitude, injuries, or just a game not translating well -- Peter Mueller (concussion), Filatov (Filly don't do rebounds), Torrey Mitchell (I think the broken leg affected his game), Prucha, Lehtonen, etc.
Anisimov was another guy who I thought never found that second gear.