Most players with a high K/D use the PDW, MSMC, MP7 only, easiest weapon in the game. Its because they can't handle other weapons. I personally have more respect when i see a high K/D player with a Sniper than one of these cheese weapons.
lol Just recently I started going for diamond camos, and my K/D (and SPM, etc.) definitely went down for it. lol But it's worth it imo, I already reached prestige master, and know that I'm a better play than my K/D reflects, but playing around with different guns and classes and whatnot hasn't been too kind to my stats lol
As a matter of fact the first diamond camos I got were for the specials, and it was very frustrating getting the Crossbow and Ballistic Knives golden, imagine the Assault Shield lol Then the SMGs, which were difficult because the Chicom, Skorpion, etc. had more recoil than I was used to. But in the end I got the diamond camos for them too, so it was worth it. Might be the only one on my friends list who has diamond SMGs, and definitely diamond specials. And besides, stats like K/D are great if you're consistently playing TDM, but even in modes like KC, it's better when you see players with a lot of kills and 30+ tags to match, not just 30+ kills and maybe 7 confirms. Shows you can kill AND play the objective, which is what the better players can do, rather than simply sitting back worrying about their K/D and dying.
I've been on diamond hunt. I'm done with AR's, SMG's, launchers, pistols, and MG's. I am doing snipers and shotties next. My KD is 3.6.