I love this Final Fantasy the combat system the best one yet, your complaining about it being repetitive well ofcourse its going to be repetitive if you just keep using Commando, Ravager and Medic, mix it up a little!

if you keep just relying on those 3 your going to get butt raped on almost every fight in a few chapters. The boss iv just not long done (Barthandelus in Chapter 9) had pretty decent music and it was a pretty fun fight also but some of the music is annoying like the bit in the forrest with Vanille and Sazh...that god awful song playing through the whole area.
It's true the CP system does throw points at you but it may seem like alot at the stage your at but the Crystanium eventually develops so far that it costs 10k CP just to move from one ability to the next.
I have never had a problem with not being able to hear the characters over the music and i don't find the story confusing, i love the story in Final Fantasy XIII i think its very powerful it draws you in and you dont want to stop playing because you want to know what happens next
I think its a great title and a must have for any Final Fantasy fan