Wouldn't Lúthien be considered more important?
She defeated Sauron and lulled Melkor to sleep.
The Tale of Beren and Luthien starts with Beren entering Doriath after the death of his warband and seeing Luthien. He is the prime mover in the tale, he is the Main Character. He's not the most important in the story, but he is the most important to the story.
That's how I see it. YMMV and all that.