Having a professional in-house editor is such a gift. In my writing career I've been very lucky to have worked with some of the most amazing editors. Not only did they make my manuscripts stronger, they taught me how to improve my craft.
I think its really important to listen to your editor. Make the changes they suggest and then read over it. Don't just reject what they are telling you--unless you have a very strong reason.
Editors work very hard to make your manuscript stronger and to better market your project. Most in-house editors are experts in their craft. They know what sells, what is popular and what isn't.
Consider what they are telling you. Try to keep an open mind. I'm so glad that I listened to the editors I've had the pleasure of working with.