Obviously the red state Democrats would all have been gone had Clinton won, but beyond that we can only speculate what 2018 would have been like. When it became clear that Clinton was going to win "in a landslide", Democrats here told us to not make overconfident predictions about 2018 because there "was no way to know for sure whether 2018 was going to be another 2010 or 2014". How the tables have turned!
I obviously disagree with this claim because of the Supreme Court, Clinton being a terrible person, Republicans holding the Senate (which wouldn't have happened had Clinton won), etc. It isn't easy to beat an incumbent president, and had Clinton won, she'd probably have been a two-term president, which would have been terrible for the country.
revisionist history is fun
or perhaps you meant a landslide similar to Trump's "landslide" victory he keeps describing