Because everyone is playing the system?
With Kovalchuk:
Clifford, +1
Kopitar, 0
Brown, 0
Wagner, 0
Lizotte, -1
Iafallo, -3
Toffoli, -3
Lewis, -3
Carter, -6
Amadio, -6
Kempe, -7
Kovalchuk, -10
Without Kovalchuk:
Prokhorkin, +3
Amadio, +3
Kempe, +3
Luff, +3
Lewis, +2
Brown, +2
Clifford, +1
Kopitar, +1
Lizotte, +1
Iafallo, 0
Toffoli, 0
Wagner, -2
Carter, -3
Those numbers never tell an entire story, and you can say Kempe was playing out of position at C, but a lot of those minuses were playing with Kovalchuk at various times. Now there are fewer minuses. They've given up 13 fewer goals at 5v5 in 1 more game.
They've also given up 10 fewer PP goals, and Kovalchuk played 7 seconds of PK time, so not a factor there. 15 fewer minutes on the PK without him, 15 fewer times SH without him. Is that fewer turnovers by Kovalchuk, resulting in the team taking fewer penalties? That's probably a bit much to dump on one guy.
They're even 3% better on the PP without him, although they've had 13 fewer PP's. Not that 14% as opposed to 11% is good. 14% is still bottom 10 since Nov 9th.
I don't like shoving everything onto Kovalchuk, because the problems have been much bigger than Kovalchuk for years, but almost every stat seems to be better when he's not there. How complicated can the Kings new system be?