Even if they took all of these: 3 Likely D ... 5 Lean D ... 4 Tossup ... 7 Lean R , they still come up short by 4. Yes, I was noticing the same thing and scratching my head as to how this is a wave that accomplishes the goal. Though I certainly would become nervous if they did take that many seats away from Republican control.
Open seats are only part of the problem. There are GOP incumbents trailing their Democratic challengers in Virginia, Pennsylvania, Iowa and perhaps elsewhere.