Gave it a 7. My game time: 124h including non-trophy related stuff (I'm confident I can plat this game around 100h if I just trophy hunted).
9 MV Barefoot X, Rosenqueen dupe, no "strategy" trophy except the explode prinny thing but that's a no brainer to do (Etna's stage and 1-1 made it easy, user created maps are also there for those who can't pull it off there) made me rate this game a bit lower than Disgaea 3. But this game is more tedious. Intelligence Director, Items Roadshow, Special Stalker, Pimp My Ship are some of the trophies that, if you didn't multitasked, will consume your precious time for the sake of that one trophy. There are trophies like Evildoer of the Year & Timid Timmy (not sure) that might come naturally if you're a Disgaea veteran but those can be "grinded".