User blog comment:Didikins/My favorite things in Black Ops/@comment-1263839-20151026120031/@comment-24756040-20151028190849

MW3's maps were problematic in that the bundled maps with MW3 were mostly either small, or medium sized with more CQC elements than not. Medium ranged sightlines were less common, with long range sightlines being even rarer. This is the reason why SMG's and shotguns are so potent in that game. MW3's DLC tried to make bigger maps with bigger sightlines, but I have no further comment on that, as I'm going based off of guesswork (I don't have the MW3 maps).

I will say this, however: sniping in Black Ops is quite problematic. Quite a few maps either completely lack sniper-range sightlines (hello Nuketown), or don't have enough of them. On these certain maps, you'll find your sniper rifle being used at medium ranges rather than long or sniper-only ranges, where LMG's and high damage assault rifles can best you.