Ironically, Gore wasn't terribly bad when he was repping for Tenn. He went 180 on alot of his platforms when he hooked up with the Clintons and alienated his home state. He hasn't been chirping out of his beak since.
I don't think the Clinton's had anything to do with his 180. They are much more mainstream than the "new" Gore. There was a time, back in the early to mid '80s, that Gore was considered a conservative Democrat and many of the FDR holdovers were pushing him towards a run at the White House. I think you are right in that when he became associated with the Clintons, his exposure to some of the far left extremists had a definite influence on his new direction to the far left.