Firing Ward now means we have the chance to pick up defense coordinators dismissed before the end of the season. Smart move. Someone was going to get axed at the end of the season anyway, might as well do it now - especially if there is someone on our radar as a replacement who is available.
I’d imagine the offensive side of the ball will see someone(s) ushered out as well. Why not now? If there are 2-3 people being let go. I imagine the offense would suffer badly (even worse?!) in that instance. And maybe their desired replacement(s) are currently employed & would wait for the off season to explore a move.
Just speculation, I’m probably the least informed person on this board.