I've been in this position as the author getting feedback and what I've discovered is that often the 'problem' was once a solution.
What happens to me is this. I'm writing, and I get stuck. I need to make a decision about something. It might be an event or a characteristic or situation, whatever - it needs to be fixed before I can move on. So I come up with a solution, it seems to work, so I carry on writing.
Aaaages later, and I've finished the draft. I get feedback, and the feedback says they don't like that solution. But, I whine. But it's got to be like that because of X so I can't possibly change it. The person giving feedback will usually back off at this stage and go on with doing more useful things while I do a little light sulking before getting back to work and sorting out the problem.
In A Single to Rome, for example, Natalie wasn't a lawyer for several drafts, she was in marketing because at the time of writing the first draft I didn't know what she did, and randomly picked that career because I know a little bit about it. I clung onto marketing for ages, before I realised it wasn't working and changed it. Once I'd changed Natalie's job lots of other things fell into place and I had one of those whoopee! light bulb moments that make writing worthwhile and the next draft was easy peasy to write.
I've learned enough to know that nothing should be sacred. If it isn't working, it isn't working and it doesn't matter what it is, it has to go. All plots can be re-arranged, and just because something was a solution once it doesn't automatically follow that it's a solution now.
So, if you ever find yourself saying, I can't change X because of Y, pause, rewind, and ask yourself "Has a solution become a problem?" And then look and see how you can fix it.