Perhaps you need to step back and consider something that we often overlook. Have you thought about changing your POV? Will that add new life to the story? Or you possibly have the wrong person telling the story. Maybe your MC isn't the best person for the job. Is there someone in your story that is stronger? Or perhaps your MC is too strong and your story would improve if it were told from the perspective of a more vulnerable character.
I'm experimenting with several possibilities as I begin rewrites on one of my trunked novels. It caught the interest of quite a few agents a few years back, but they all ultimately passed on it. I haven't figured out what will work best in this case, because it's still in the first stages of revision, but several ideas are floating around in the vast wasteland of my mind. What about alternating POV? Have any of you had success with that? It sounds rather complicated to me, but that might be what this particular novel needs. Both of my MC's are rather strong, and I wonder if they have been vying for the lead role all this time, and that's why it didn't quite gel.
How about you? Have you ever thought you had the entire book worked out and then second-guessed yourself into major rewrites? Did it help?
Have a great week, everyone. Hope you accomplish all your goals.