I guess I'll get more hate by this response but I won't let it bring me down
In Black Ops 2 demolition, with the static spawns where each team has their base, crossing the halfway point of the map is huge for map control. Wouldn't you rather be able to run towards their base and get kills then have them all up in yours killing you? A map like slums is a perfect example because whichever team has the fountain/statue area in the middle can dominate regardless of which side they're on because the other team is only stuck on their side of the map. With a 1.1k/d you'll just be getting a kill and dying right after, so it's hard to gain map control to complete objectives. If you could hold your own and be able to win gunfights and know where to go and which gunfights to avoid etc.., then the other team is pushed back making it easier for you or teammates to complete an objective.
So if you had higher than 1.1k/d, you wouldn't need to plant 4-5 bombs a game which is an absurd amount. If a whole team combined had that many plants, then the game must've been a huge battle. With a higher kill to death ratio, you'd be able to plant 1 bomb a game (possibly 2) and get them destroyed. The other team would only have their side of the map to play and wouldn't be able to have a chance to defuse. It's pretty hard to spawnkill if you have no map control cause if you do somehow break free to the other side, the other team will be outnumbering you and you won't last long and you won't be helping your team.
And props to you with your defuses. Unless you kill the planter in the first 5 seconds or so, defuses can be difficult to achieve. Usually, you can't just run in and defuse. You would normally kill a person or two and then place a betty or shock or something in front of you, that way they are slowed down when they come back and then you can hopefully defuse safely. It usually takes more than one teammate to have a defuse go through too.
HOWEVER, (another comment that will get me hated), if you had higher than a 1.1k/d, most games (not all) the other team wouldn't even get a plant off, especially if your team has solid map control. Teammates that stay back and camp bombsites aren't helping because the enemies have map control and will easily flush out the bomb area and then move up to your base, which is exactly why i have about plant to defuse ratio is 3.00 because defuse opportunities don't come along as often.
In MW3, most games would go to overtime and it heavily favored offense. This came actually favors defense, which makes getting plants off pretty hard and it feels rewarding getting 500xp when you finally plant and destroy. And because defense is favored, you should easily win your defense round and then if you're good enough to destroy bombsites, most games end with a 2-0 victory