One state that I'm not sure is either underrated or overrated (since I'm not sure that it has any particular significance at all yet), but that I nonetheless find fascinating, is KS. I don't think KS will vote D anytime soon, and the fact that it trended D may not even mean much, but I still think it's one of the most interesting "factoids" of the election.
Kansas has a very young and educated population, and I just think Trump and Clinton were both horrible fits for their respective bases in the state. This was evident with both Cruz and Sanders winning their respective caucuses handily, and also the hard third-party swing in the GE (2.3% in 2012 to 7.4% in 2016). I don't read too much into Kansas 2016 except that they just weren't crazy about the choices they were given.