Colorado is a creative class 'latte liberal' state, Hillary wont have the same appeal as Obama did among those wealthy suburban socially moderate suburbanites like Obama did. Hillary is a very strong candidate, but she certainly has her weaknesses in certain states.
I would also expect her to run poorly compared to the national average in states like Virginia (Nova) , Oregon and Washington. Obama was a perfect fit for those states, like Hillary seems to be in the upper south.
It might run deeper than this. Obama in 2012 lagged Kerry 2004 in many of the Western ski counties. Also, in VA/OR Hillary has been polling even with or better than Obama generally. The problem states for Hillary seem to be CO/IA/NH. Libertarian/dove issues?