Well as much as I loved SWAT in Halo Reach, SWAT in Halo 4 doesn't compare.
Lets start with the maps, some of them are far to big for this game mode and the other thing is just the sheer lack of maps. The same 3/4 maps get voted every time and so i find myself getting very bored, very quickly.
Weapons: I despise the BR in SWAT, nothing worse than getting sprayed the hell out off by noobs slowly walking round corners. What happened to quick, accurate shots? I agree that the DMR should be the only weapon. The pistol as well is just as good as any rifle and needs sorting out, its a side arm not a starting weapon.
Also some other SWAT game modes would be nice as well eg. swat magnums, swat oddball ect.
One last thing, I don't know if anyone else has the same problem but the cross hairs after sprinting take so long to appear! I dont know if this is me being picky but compared to reach it just seems slower at appearing.
