Vita's online infrastructure is only as good as where you are, what connection your hardware SKU can access and what restrictions the developer has put into the game.
That will be the killer of "CoD anywhere!". Most players won't even have the 3G model, 3G is shit anyway (although the chances of the game even supporting online multiplayer over 3G are slim to none IMO), most public Wi-Fi is throttled to hell and sparsely available, both network connections kill the battery and serious PS3 players aren't going to want high-latency, regularly dropping Vita players fucking up their games. Similarly, serious players aren't going to want flaky network connections fucking up their stats.
The potential for the game is amazing, but the reality will be nothing near.