This is Koei, and a Koei sequel. It is not a leap ahead, but a sequel, so if you like Koei and SW, you will like SW2.
The game itself is a sequel to Samurai Warriors, and in the Koei style it is not some huge leap forward. There are a few new elements, a TON of new moves, characters, and styles, but not a new gameplay mechanic. Of course, this is what fans of the Dynasty Warriors and SW have been eating up for years now. It may be that this is offensive to some overweaning individuals, and I myself would prefer that Koei advance itself in addition to these... content upgrades, however it is still a fun game for fans of this style.
HOWEVER... I am not reviewing the 360 version, because I have not played it, but I cannot IMAGINE why it would be made. This game is not grapnically or stylistically next gen, so a release on the 360 is a pure moneygrab. This game is not straining the PS2, believe me.
Some of what the gamespot review says is true, the voice acting is absurd, as always, and the gamesplay is the same. However, I was someone who played Samurai Warriors 1 to distraction, and I would gladly play it all over again with a new cast of characters, some upgrades effects, and new moves. That's what this game is. Is it a 9.0? God no. Is it a 6.0? No. This is a 7.0-.7.5 with a HUGE sign that says "If you loved SW and would kill for more, ANY more, this is a 8.5 for you! If you hated SW, and can't stand dynasty warriors, it's a 1.0. Duh."