I'm working on what will probably be the most complex thing I've written yet. I'm planning on making it novel length so I've been spending more time than usual mapping out the plot and characters, etc. Originally L.B. was going to be my MC. The story (originally) revolves around her. But one of the characters that was meant to be more of a secondary character (C.F.) has a stronger voice, if you will. C.F. is more present in my head, so to speak, than L.B. If I make him the MC it will be a very different story but I'm seriously considering it. I've only got about 4k words so far so it wouldn't be that difficult. Has this ever happened to you? Have you changed MCs or had a character that stood out so much that you had to give them more of a part than you planned? Thoughts? Comments?
Could the story in any way be done through a second person view? Maybe a different perspective would allow you to work it out.
It has happened to me, kinda. In my current novel, there are two main characters, G and K. The original story, in my mind, followed G exclusively. But I realised, after I had written the first chapter, that it would be much better to begin with K. After I started writing with K, his character advanced well beyond the boring mannequin that he was to begin with. Now, I alternate between the two. The focus is still on G--he will have the vast majority of chapters, I think--but K definitely deserves several of his own. It has made my story infinitely stronger than it was, giving it the depth I wanted, but wasn't sure how to achieve. You may very well be better off changing your story, if you think you can do a better job with the 'secondary' character. Heck, my secondary just might take over my story, too. If you've written four thousand words and still can't give your primary character a voice you'd like to write in, something's gotta give. Change the character, dig a little deeper, or shuffle her off to a secondary role. I'm not sure what else you can do.
Oh yes. This has happened to me. I offered a staring role to someone (Gabriel) and the he got mad stage fright. I discovered later that I had no reason for him. He was just a narrator and thus had no real personal presence. I had to go back and decide the why of him before I could go forward with him. He almost ended up in file 13.