The fact is that it is probably not just EA alone but the developers.
Most developers want to use the high end software, but dev tools for the Wii seem to be from previous generation. Add the frustration with the tech to the fact, that most publishers have no idea (outside all things Mario and lately fitness) what will sell on the system, causes the hesitation to fully support the Wii.
But as others have said, the lack of support, isn't all on the publishers or developers. This is the third straight console generation that Nintendo's choices with hardware have alienated them with developers and publishers (N64-cartridges; GC- 1.5 GB mind-discs instead of full DVDs; Wii- a weak powered system and motion controls).







