While I get your point I still think Iginla, Forsberg, and Sakic were all better players in the years you were talking about...Naslund was for sure top 5 for 4 years which Tkachuk never was.
Also one more thing...Naslund having a better 4 year peak is great however the thing that pisses me of in general is the flack Tkachuk gets for his career and not his peak...Adjusted goals puts Tkachuk at 21st all time for goal scoring.
Well I'm looking at the years of 2001-'04 in that three year span. Naslund won a Pearson in that span. Forsberg was injured too much, Bertuzzi wasn't as good as Naslund so basically you have to ask yourself which player was the best in those three years combined? Iginla, Sakic, Naslund, Lidstrom and Brodeur are my picks. Iggy and Sakic both had sort of "off" years in 2003 while Naslund never had an off year. I honestly think you have to give Naslund the award as best forward during that span.
I think Tkachuk's goal scoring is fine, but there are a lot of players - even from his era - with as many or more points that I wonder about getting into the HHOF. Those players often offset things with a better playoff portfolio. Tkachuk doesn't have that and while I am not saying he needed a Cup, I don't think there is any reason that he couldn't have gotten out of the first round in those years - just once.