Riccitiello went on to explain that this is largely due to Wii developers "producing less art than for high-definition games." As a result, EA will be giving the Wii as much developmental emphasis as the 360 and PS3 enjoy collectively, seeking to "rival Nintendo on their own platform." If the announcement of Dead Space for the Wii is any indication, more emphasis will also be put on bringing more hardcore experiences to the console, rather than ports of the latest Madden or block-based puzzle games.
Source – Ricitiello: Wii development is 'a third to a fourth the cost' of next-gen
Source – Ricitiello: Wii to get 'half our emphasis'