This is inevitable. Just because something has been written from scratch, that doesn't mean it necessarily feels original. There are only a limited number of plots available (the number varies depending on which academic you read) and how original something feels depends on whether the viewer has seen a similar treatment before.
It's a bit of a lazy line in a critique though. It would have been more useful if the writer could have said what it remined them of, then you'd have had a better understanding of why it "didn't feel original".