I mean, maybe I'm wrong and every midterm election will be an easy win for the party that doesn't control the White House, but I kinda doubt it. 2018 will be very telling, in all honesty.
I guess it depends on what you mean by an easy win. Historically, the "out party" almost always picks up seats. It's such a consistent pattern that it would be unwise to bet against it. The question is really how many seats. The fact that Democrats need to win the House PV in what is basically a landslide is a testament to how big the GOP advantage is.
Also it depends on the coalition that Democrats get to get a house majority. We could win the popular vote by a couple points and win a house majority or if polarization is super super strong we may have to win it by 12 to 13 points to eke out a bare house majority.
