Kirkwood destroyed the show, the effect of which is still on screen. In my opinion, he absolutely butchered the show within an inch of its life.
I still believe DTC was kirkwood's successor, but he was contractually unavailable, hence Lorraine Newman filling in. She sorted out a hell of a lot of mess that Kirkwood left behind. If nothing else, re-building the Beales and sorting out Kat make her the superior EP compared to Kirkwood.
I believe her job was to give DTC a clean sheet upon which he could build. She didn't make any big decisions or hasty changes, she instead stabilized the show, and whilst at the time it was frustrating to see her simply papering over the cracks, it was absolutely necessary. As a viewer, the summer of 2013 was a dreadful period of the show, but I believe it was needed to rebuild the show from the feet up.
So, in short, Kirkwood was nothing short of disastrous for EE.