The problem with this one is that there is not enough info available to say if it will be either a re release of the original PS2 version on the Wii or an actual remake of the the PS2 game.
Comparing the graphics of the two versions i would guess it would be a re release so i guess it would be better just to add a new release date to the PS2's versions its game page.
The little quick blurb says extra characters and levels, so I guess it's no mere rerelease? According to a quick google, it's an enhanced remake. At least one confirmed new character according to a two week old Famitsu. Probably going to be on par with the differences between Disgaea: Hour of Darkness and Disgaea: Afternoon of Darkness.. Nippon Ichi has been doing a pretty decent job of not just rereleasing their past work.
I vote keep, but flesh out with additional information where possible (I think that Famitsu article is the only source people are using right now).