Because no one knows anything about it
No previews other than a bit about franchise, a few off screen vids, one producer doc vid, a few pics and thats it. Over at wiimakemadden twitter they said most of the marketing muscle went toward the 360/PS3 which is why there has been very little info out for the Wii version.
This is the info I've gotten from wiimakemadden.
Whats new/in
Re-designed Franchise
Weather effects and uniform/field degradation.
Gameflow and Arcade Playcall(Game flow not quite the same as is in the 360/PS3 version)
New animations(more than 300)
Changes to the UI(user interface)
More uniforms
Whats not in
No create-a-play/player/team
No wiispeak
No changes to presentation
No online leagues
No classic controller support
No President Obama