3ARC has a way of putting together a great variety of map sizes and styles. WAW had larger maps down to very small maps. Same happed in BO. They seem to know the exact size needed for the type of game COD is.
There is no way that COD should have BF3 size maps. They are much too large for a quick arcade shooter like COD. They are good for a simulator style game like BF with the air and ground vehicles.
A game of TDM would never hit the score limit if the maps are that big. To many campers in COD.
Also, they would need to incorporate bullet drop in COD on maps that large. Sorry, but I would be pissed to get taken out by an M16 at 1600 meters. lol
Personally, I feel that WaW had the perfect range of map sizes. Some were very large, like you want. Some were big, like what balances a fast pace and decent spawns. And few were small, where people have chaotic fun and is their preferred private match map.
When I think about map size, I think not only of the width of the map but the height. The Call of Duty series has been fantastic in exploring multi-level maps that give more room to spawn/run without creating large lines of sight. I prefer these maps to the expansive, one level maps of BF, Ghost Recon and Homefront. Think of it as COD building highrises instead of ranch homes. More room, less footprint.
As a RunNGunner nothing trips me up more than hauling arse all the way out to where the action is, then dying and having to make the trip again. >.<