Well halo isn't based of games. The original stories were books. According to halo's story and history, the games are based of books, comics, and the anime. Also halo has evolved around master chief only. There were also some books that started to stray off the path of master chief. People only say halo will start to suck bc of the new heroes. But the main story will stick to master chief until they decide to let him die

I don't think Halo sucked because of new characters. I think it sucked because they got away from a multi-player that was perfectly balanced in favor of one that adopted classes and such. They also got rid of their most popular weapon in the Battle Rifle

No they got rid of dmr which was bad too. The battle rifle was redesigned and it looks like it will get the burst and single shot fire mode basically making it part dmr. That's the only difference for the battle rifle now.