It's been a while since I watched the drama of the same name, but if memory serves me right, even though both stories are based on the same premise, they were still fairly different from each other. And each were enjoyable in their own right.

The idea of loving what's inside a person is a noble and beautiful sentiment, but I'm glad the struggle of having to cope with the emotional toll of everyday waking up to a stranger next to you was portrayed. In the drama, the ML could always recognize the FL so they didn't have to deal with that, but I think that aspect added a layer of mature emotion to the movie.

I think it'd be fun to see this premise in a horror movie. The thought of a stalker being able to literally change their whole appearance every day is terrifying and would totally work as a scary movie.