That said: I think it's fair to say there was no "blue wave" this year. The typical loss for the President's party in the first midterm is 28 seats in the House and 3 in the Senate. At this point in the night, it looks like the Democrats will pick up 30+ seats in the House (to gain control) but lose four seats in the Senate. (AZ still in play).
But as Chris Wallace noted: the Democrats had an unusual number of Senate seats to defend this year so it's not surprising that the GOP picked off a couple of Senate seats in red-leaning states.
So Republicans won in Republican-leaning states and Democrats picked up House seats where the Republicans were vulnerable. So: expected but not "wavy".