You can not just republish them. They would have to recode the maps to include the weapons and equipment for MW3. They can not ust change a file extension and make it work. Each and every weapon in the game is coded in to the map file iteself. Its the same reason they can not just easily add new weapons to the game like everyone wants all the time. And yes republishing them would cost, for they would have to pay MS to publish them on the xbl servers. Every map pack that comes out has to be paid for to MS to host it.

As towards giving examples it is not possible for there is numerous places to defend from distance on many of the maps. Seatown for example.. you can guard from the tower or the red buidling or even near the well depending on which way they are coming form.

Playing with randoms is always a pain in the ass, but I try to cope

I'm actually aware of strategies on Dome, but I have a personal disdain for the map as it always turns into a clusterfuck of mindless shooting and sprinting. The flag in the office is by far easier to defend then the flag in the Dome. Partly because of the all the explosive material in the Dome and the wide open spaces inside and outside the office, not to mention the line of sight (hallway).

Portable radars + Claymore/betty will work wonders in just about every map.

As for Downturn, that map left such a sour taste in my mouth while playing TDM that I refuse to play it at all.

Yeah, World at War is still hands down my favorite shooter, and would be the perfect FPS if it only had Support package, deathstreaks, and Combat Training.

But no defensive attributes also makes the game more fun; shooters should be fast-paced, not tactical (which is why Battlefield isn't that great of a shooter). Notice how there is a massive reduction in the amount of complaints of campers, which was why Modern Warfare 3 is such an offensively-based game (the purpose of Support and deathstreaks is to flush out campers, which do nothing but slow down the game and make it boring for everyone).  If you want tactics, strategy, and taking things slow go play a RTS.