I don't see reason because narrow board turn faster then wide, and there's none =) Check out physics lessons.
The only advantage of the narrow boards is faster edge-to-edge performance. But you gotta know what is it, and be able to carve the board, and want to get a carved turn.
Unless you don't want faster edge-to-edge peroformance, get a wider board, as it can give you much more: more angles without toe-drag, better float in powder and probably better landings.
I own NS Legacy 174 with 27.0 waist and Prior win 20.5 (not 25 =) waist. 230 lbs with US13.
ps. waiting for my custom 28 waist freecarve machine..