Yeah, I feel like this whole "Why-isn't-Mogilny-in-the-Hall-of-Fame?" thing is starting to become a bit overblown.
The main reason he's not in the Hall of Fame is... he wasn't a Hall of Famer, by NHL performance. I can't speak to his international hockey credentials much, but maybe that pushes him up (or doesn't it? I don't know).
And yes, he defected successfully... but so did the Šťastný brothers, like, a decade earlier.
People are unfortunately starting to make this into a big deal, when it really isn't. I'm well aware of Hockey Ref's "Adjusted Stats" flaws, but to give Mogilny's NHL results some context:
Player with TWICE as many 'adjusted' 40-goal seasons as Mogilny:
-- Ilya Kovalchuk
Players who have more 'adjusted' 40-goal seasons than Mogilny:
-- Rick Martin
-- Peter Bondra
-- Theoren Fleury
Players who have the same number of 'adjusted' 40-goal seasons as Mogilny:
-- Joe Pavelski
-- John Tavares