what if every few years every seat up in the us house had to be open

[freepcrusher]

by that I mean everyone has to retire. What I'd be interested in is if it happened in wave years like 1994 2006 or 2010. Would the strength of the wave cause seats that might otherwise go to the other party to stay with that party (for instance the Kirk seat staying republican in 2010). Another thing is would it increase either party's gain in congress?

1994 is an interesting election because if all the seats were open, the republicans easily could have gotten to around 260 or 270. Here's some that off the top of my head that might have been won by Rs in an open seat:
AL-03
AL-04
AL-05
AR 1
AR 2
CA 3
CA 15
CA 18
CT 2
FL 2
FL 5
GA 9
IL 17
IL 19
IL 20
IN 3
IN 9
KY 3
KY 6
LA 3
MI 10
MI 12
MN 2
MS 5
MO 4
MO 6
MO 9
MT AL
NC 8
ND AL
OK 3
PA 4
PA 11
PA 12
SC 5
SD AL
TN 6
TN 8
TX 1
TX 2
TX 4
TX 5
TX 11
TX 12
TX 14
TX 17
UT 3
VA 4
VA 5
VA 9
WV 1
WV 2
WV 3
WI 7

[muon2]

Neutral redistricting requirements would make a significant difference. It can't erase incumbency, but it would likely increase the number of competitive seats.