Mike Gravel of Alaska for President. Opinions?

I'm sure you've all heard that former US senator from Alaska Mike Gravel  has decided to run for president in 2008.  So far in reading about his life and career I think he could be a decent candidate.  He has a certain badass factor to him ala Brian Schweitzer (hell, his last name is Gravel for christsakes)  but with a lot more Washington experience.  He has lefty and at times wacky politics, but they tend to be populist.  For instance he supports the idea of having ballot initiatives (which I consider to be the unholy curse of the west) on the national level and dissolving the electoral college (which I agree with).  He's a national transit advocate too which I enjoy.  Anyway, he seems to be the type of candidate that could get elceted on his gravitas despite his politics.  What do you all think?  I doubt he will even be a serious consideration in the primary, but do you think he could be a dark horse?