1. if you steal an enemy gun then you won't lose it even if you change your weapons.
2.a snow map like blizzard or chain reaction(if you played it)
3.maps are remade for fun instead of copies of the single players maps only with a few pathes and doors open
4.instead of having weapon sets have just weapons. like "no M16s" or "STG 77 and IW only"
5.if you don't have a gun with a scope it should go straight into your bicnoculars (sp?)
6.in the single player the A.I. reacts instead of standing like blind and deaf morons. like when you shoot one terr. the other one sees it and tries to hind.
7.have the C4 like a bomb that you can place any where and blow up yourself. i know this is already posted, but just saying
8.a map that is just an empty city. lots of houses, tables, and things like that.
9.have a trip wire claymore
10.the RPG should get only one shot not 2 when only one RPG is selected
11.let the seals have an AK like in sc2
http://world.guns.ru/assault/as04-e.htm
these are just some ideas, but i think that they are some pretty good ones. anything to add?