WHL leading scorers from 88-89 (full disclosure the years before this they had a number of NHLers who led the league in scoring including Cliff Ronning, Rob Brown twice, Ray Ferraro and Joe Sakic)
88-89 - Dennis Holland no games in NHL
89-90 - Len Barrie - 184 games in NHL
90-91 - Ray Whitney - long career in NHL
91-92 - Kevin St. Jacques - no NHL games
92-93 - Jason Krywuluk - no NHL games
93-94 - Lonny Bohonos - 83 NHL games
94-95 - Daymond Langkow - long NHL career
95-96 - Mark Deyell - no NHL games
96-97 - Todd Robinson - no NHL games
97-98 - Sergei Varlamov - NHL superstar, 63 NHL games
98-99 - Pavel Brendl - NHL superstar 78 NHL games
99-00 - Brad Moran - 8 NHL games
00-01 - Justin Mapeltoft - 38 NHL games
01-02 - Nathan Barrett - No NHL games
02-03 - Erik Christensen - 387 NHL games, servicable player
03-04 - Tyler Redenbach - No NHL Games
04-05 - Eric Fehr - still playing, solid NHLer
05-06 - Troy Brouwer - still playing, solid NHLer
06-07 - Zach Hamill - AHLer
07-08 - Mark Santorelli - AHLer
08-09 - Casey Pierro-Zabotel ECHLer
It appears you get a NHLer player leading the league in scoring about once every 3 years or so.
Hobey Baker Award Winners
http://en.wikipedia.org/wiki/Hobey_Baker_Award
NHLers from 89-90 to 08-09 include Kip Miller, Scott Pellerin, Paul Kariya, Brian Holzinger, Brendan Morrison, Chris Drury, Jason Krog (borderline), Ryan Miller, Jordan Leopold, Matt Carle, Kevin Porter (borderline) and Matt Gilroy (borderline).
It appears that the Hobey Baker award winners are more likely to become NHLers than the WHL leading scorers.