Nice work, uojoe82.
Now, I wouldn't want to flaunt any of them high falutin' advanced statistics that I didn't work out all on my own...so I will just post Nash's first 6 years of stats from basketball-reference.com.
I'm not sure if you forgot, or weren't aware, but Nash never played a full season until his 6th. He was always injured and often played limited minutes off the bench. While the comparison is there, I am not sure it is as accurate as you would like it to be.
Nash was also on a team that had multiple established scorers/players like Sam Cassell, Jason Kidd, Kevin Johnson, Michael Finley and Dirk Nowitzki.
Nash also never sported a usage rate as high as any of Lin's (but that's another one of those advanced stats). Nash averaged about 6.5 shots per game. Lin averages above 10.
Sure, Lin has plenty of room for improvement. I don't think anyone is arguing that. This whole debate about his ceiling is borderline ridiculous as nobody--NOBODY--actually has a clue.
By the way, it is possible to support a player that one views as mediocre. I support Casspi. I support Garcia. I support all of the Rockets. That has nothing to do with their potential or status on the team.