If the Wii version gets good reviews, it may be the first test to see if Wii owners are willing to purchase what many consider to be a "hardcore" 3rd party shooter. This is the first big name shooter that I can remember coming out with a Wii version along side the PS3/XBox/PC versions.
If it sells well, expect many 3rd parties to jump on the Wii hardcore bandwagon.
If it does not sell, expect a steady pile of casual games from 3rd parties for the Wii's lifetime.