I like musical movies but I am very strict for my training in cinematography. Musicals must speak and convey emotions with music and songs. I agree with you that producing a musical with all the original songs is a great challenge and a great risk but it can also be the most attractive.
Jackman is great for this kind of movies because he has great charisma, he knows how to dance and he knows how to sing. His choice was very right; however he just could not lift this film.
My rating would be 7/10
A big hello @smokerings