We should remember we have (and are guaranteed by our Federal Constitution ) a Republic form of government, especially as opposed to a Democracy.
The Center for American Progress report on how democracy is doing in NH presumes allowing 16 or 17 year-Olds to pre-register or allowing people to vote over extended time enhances our poltical process. I doubt those assumptions and the consequent rankings. I'm unaware of any evidence that such changes would change electoral outcomes, never mind improve them (unless one advocates for less informed voting ).
What they would do is move us further from a Republican form and closer to a Democracy.
I believe that improving our ranking by these measures would significantly undermine our Constitution.