I agree that they casualized Halo 4 too much by copying CoD, but I don't think the music was horrible, it wasn't as good as Marty's iconic Halo music, but it was good in it's own way. I do feel like 343 needs to license some of Marty's most iconic Halo songs though, and mix them in with some Neil Davidge originals. 

Halo Imo story is much more important and 343 did a much better job than Bungie ever did with story, Bungie owned them with multiplayer though, Halo music was pretty good, Marty was better though, Multiplayer is a easier fix than having a good story, If they listen to community feedback it can be made awesome very easily

You have to understand what what 343 wrote, came off of the work Bungie and the books/fan fiction was able to create.

I'm pretty certain that he's a longtime Halo player, as are the other pro Halo players that 343 have hired. I'm pretty sure that at least one of those Pro Halo players went on record saying that they wanted classic Halo multiplayer to return, so having him work there is defintiely a good thing for Halo 5.

• Linda is the best sniper out of all the Spartan II's (she once shot two targets fast enough that even John couldn't tell which she shot first).
• Kelly is the fastest, capable of running at nearly 40 MPH in short burts. She also has an increadible tolerance for pain, surviving serious injuries on many occasions.
• Frederic is the 2nd best sniper and the best spotter. He's also particularly skilled at knife fighting. He's also the 2nd best leader behind John. John once said that Frederic came in 2nd place in every single area when they were in training, John thinks that he pursposefully held himself back in many areas so that he wouldn't come in first since he was shy and didn't want to stand out, so he's perhaps the most exceptional of all the Spartan's even though he hides it. 
• And John is of course the best leader and the luckiest of all the Spartan's, which is why Cortana chose him. 

I really do hope that 343 puts them in this game, they need someone to provide dialog now that Cortana is gone and since John isn't very talkative. The fact that 343 put Linda and Frederic in Forward Unto Dawn is hopefully a good sign that they plan to introduce them into the games. Really there's no reason why they couldn't introduce them, they returned to Earth after the events on Onyx a few Years before Halo 4, and John returned to Earth at the end of Halo 4, so it stands to reason that he would have met back up with them and been assigned back to Blue Team as leader.