Okay, Musou Orochi 2 is good. Really good.
-The game suffers a bit visually; DW7, Hokuto Musou, and I think even the ported-up Sengoku Musou 3Z look better, but MO2 seems to have way more enemies on the map and on-screen compared to those games. The first stage you play even has a giant multi-headed Orochi-serpent blowing fire down onto the map as an additonal hazard. The frame rate fluctuates, but it's nowhere near as bad as DW7.
-Only played a few stages, but haven't seen any new enemies yet. It's essentially the same line-up from the previous game.
-Between stages, you move around a small "home base" area similar to Dynasty Warriors 7. You can speak with other characters, buy weapons/upgrades, get info, change characters, etc.
-There's only one campaign mode now, but it seems to be HUGE. After the intro stage, the game seems to have divided itself into two paths. One takes you back to previous events in the main(?) characters' lives. I was skipping through a lot of the story, but it appears that new character Kaguya appears and allows them to go back to the past to change the outcome of events that led to a lot of other characters' deaths at the hands of the Orochi forces. You must have whoever's stage it is on your team in these levels but can choose whoever you want for the remaining teammates. I started playing these levels, and just like the previous games, you get Dynasty or Samurai Warriors-themed stages, with Orochi elements "invading" the landscape. Got three more characters for clearing one of these stages. The other path looks like it's going to progress the main story further.
-There are power, speed, technique, and wonder character classes. Not sure if there's anything more. So far my favorite character is Samurai Warriors 3's Hanbei, who is awesome here just like he was in that game.
-Each character retains the techniques from his/her game, complete with musou super attacks themed in the same style as the game they came from, so you get different effects depending on whether or not the character is from DW, SW, or MO.
-The game play feels more like the other Orochi games/Samurai Warriors/Dynasty Warriors up until DW5 than Dynasty Warriors 7; the controls feel tighter and you feel like you have more control over your character, plus everyone can do jump+triangle attacks again.
Can't wait to play this more.