Think this may have something to do with the matchmaking process. Try to check this article, Activision Support
Also, I think it is better if you set your NAT Type to Open.
Hope this will help.
It has everything to do with the match-making process. SnD traditionally has a fairly low player population. That alone will substantially increase the likelihood of seeing the same players over and over. BO2 is also "last year's game" so the game itself has a relatively low player count, making the SnD player count that much lower.
There's nothing you can do about it except get more people to play BO2 SnD.
This is a bit off your point but you should really try opening your NAT. Search the BOII forum. There is a guy a while back who linked a vid on how to do it easily. I'll make a big difference in your game. Your bullets will count and those guys you keep coming across will regret meeting you so much.
As what Yppecaye_the_Dogged said, you can try opening your ports by following the steps provided in this article:Activision Support (Port Forward and NAT FAQ).
Hope this one helps. Thanks.
Yeah, I don't recall seeing the bit about your NAT being moderate previously. What Yppe said is very critical. The link SMW provided will help ... to get your NAT open, read any of the following three threads then go to the site linked beneath them ...
Personally, I learned about how this stuff works through Macc's thread then used Fox's and Falcon's threads to actually do it. I think I asked Fox some questions about the actual ports, as well, that helped me finally get it right 100%.
In any case, even once you have all your ports forwarded, low player population may make it difficult to find a lobby sometimes. I am 60% certain that all three studios have implemented some new coding that forces players with similar connection types and qualities to play together (a recent interview with one of the SH devs all but confirmed my suspicion of this).
You've got to get that NAT open, bro.