I think its more who comes out. In 2006, a lot of young people were very interested in the election because they were not happy with Bush and the war. In 2010 and 2014, the young people really didn't come out like they did in 2008 or 2012... so I think in 2018, you're going to see young people come out, especially millennial women... African Americans I think will come out in larger numbers....
This is overrated. While it's true Democrats maxed out with Millennials in 2006, they carried every other age group that year. Same in 2008 when Obama won every age group but the over 65's. Drumpf got everything but Millennials. The subconscious ageism many Democratic strategists apparently have must stop.