Reviews for a Musou game are bad by definition unless you're Jim Sterling because no god damn journalist understands these games besides him.
Seriously, do *not* count on reviews for this. A lot of people are clueless and dismiss them as just exercises in button mashing while it really is much deeper than that.
There *are* bad Musou games - Hokuto Musou 2 is particularly bad (I liked the first one, but they took away everything that made it unique) but they are all different enough that they feel like variations on a concept.
Gameplay wise, Dynasty Warriors != Samurai Warriors != One Piece Warriors != Hokuto != Gundam Warriors != Warriors Oroch != Hyrule Warriors. They all differ greatly. At first glance, they all have a similar feel, but their underlying systems are all different. Combos, progression, weapons, skills, etc. are all wildly different for each game.