What I'd like to change if I had the power to do so, in no particular order.
1. No more quickscoping. No need for a debate, it's a fact that this is absurd. You should only be able to scope in from a crouched or prone position. Time to add some realism to what has become an out of control exploit, snipers are heavy and manuevering them while on the move within the game should reflect this. Provide larger maps so that snipers can use their weapons as designed. Also, it should no longer be possible for a sniper to remain scoped in once shot. Of all the absurd elements of the COD franchise, the fact that someone can maintain their ability to scope in while getting shot might be the most absurd and unrealistic.
2. Drop shotting and jumping to avoid being shot needs to end. The act of going prone should take a minimum of 1.5-2 seconds. Once fully prone another 1.5-2 seconds should be required before a player is able to reposition their weapon and begin to fire. Jumping should all but eliminate your chances of landing a shot on an enemy.
3. No more music EVER while a game is in progress. It's distracting and serves no purpose whatsoever. Also, the sound notifications when you rank up or complete challenges need to go as well.
4. In MW3 predators are almost always centered on the top player in the room. I routinely have the highest K/D in the lobby, and I've noticed that by far the majority of the time when an enemy calls in a predator it's centered directly on me when they first open up the laptop. I've also noticed that when I use predators I often end up killing players with high K/D's. This is something built in to help "balance" the game, clearly. But in reality it's just a punishment for being good, it needs to end.
5. Killstreak rewards should be VERY difficult to shoot down or destroy. I typically use the Pavelow in MW3, two shots from a stinger take it down immediately, sometimes one. This is absurd. Twelve kills in a row and in literally less than 5 seconds your killstreak is destroyed? No, there's no logic there. At the very least the time it takes a launcher to lock on should be DRASTICALLY increased. Instead of the 2-3 seconds it takes to lock on as is, it should be changed to 8-10 seconds AND require a minimum of three rounds. Yes, this means that more than one person on a team should be required to help bring down choppers of any type. It's called team work and it's about time people start to learn what that means. I run a stealth class 99 percent of the time but I still make my secondary a stinger to help the team. Many of my deaths result in me trying to shoot down killstreaks because nobody else bothers to. Require more than one person to help out and this will change. Even if one person does end up having to take down air support on their own (they fire two rounds, die, and fire another), this would still require around 30 seconds to accomplish. If you earn a higher valued killstreak 30 seconds of use should be automatic, so this is fair.
6. Killstreaks should not contribute to higher killstreaks, but EVERYTHING should count towards one. Assists, shooting down air support, destroying claymores, TI, or any other type of equipment etc. Even situations such as a teammate has been stunned and you come to their rescue and take out the enemy for them. Every action involving team work should be rewarded, and not just by some useless challenge.
7. Those who use grenade launchers should be limited to a set number of rounds per MATCH. This will help reduce the amount of "noob tubing", which has plagued this game for too long. I understand the purpose of the attachment in real life, but in a video game kills should require more than one push of a button aimed in a general direction. No more than three rounds per match per player.
8. Upon spawning each player is invincible to everything other than gun fire for 3 seconds. Quite often I'll spawn, run a few steps and die from a claymore, or right into the path of a grenade or flash bang. Highly annoying and using this system it would be a thing of the past.
9. No more akimbo OR fix hit detection. The combination of akimbo and horrible hit detection is brutal. Kills are handed out unfairly because of this, AIMING should be a requirement, not an afterthought.
10. Ability to swap out iron sights. At times there are guns that I'd like to use, but I just cant get over how horrible the iron sights are. If you could change the sight to something you prefer, you'd be more eager to try new weapons.
11. Getting shot first should make it nearly impossible to return fire accurately.
12. No death streaks.
13. K/D is not impacted in any way when playing objective based games. This would lead to more people caring about the actual result, not protecting their stats.
14. The return of specialist/support/assault killstreaks
15. The return of unlimited sprint using Marathon, as it was in MW2
16. Gun shots, silenced or unsilenced should NOT show up on the minimap. Players should have to rely on their concentration and ability to determine where the firing is coming from.
17. Viewing the minimap should only be available as a killstreak.
18. Assign a different kill total, or point total, to each killstreak. Players should be able to select any killstreaks they want, not have to exclude certain rewards because two selections have the same number of kills/points associated with them. For example in MW3 I believe nine kills in a row is reaper/overwatch/strafe run. You should be able to select all three as your rewards if you wish. Stop limiting us to what we can select, this game should be about more options, not less.
19. Return of night vision from MW, and at least two night maps. On these maps have certain areas that are PITCH BLACK.
20. Limit the number of grenades people have. In fact, just as I stated earlier that grenade launchers should have a limit per match, so too should grenades in general and flashbang/consussion grenades. I just feel that people spam these too much and it leads to many fluke kills. People should be forced to use their items wisely, not spam them knowing that once they die they will get a fresh supply. 3 grenades and 4 flash/concussion grenades per match per player.
21.Replace the knifing system with gun butting. The idea that a soldier could be running full speed and in the blink of an eye reach for and pull out their knife, and slash at an enemy is absurd. However, a player reacting very quickly by smashing the butt of their gun into an opponent is much more realistic. Two strikes required for a kill. This ends panic knifing and requiring two hits gives both players a chance to react. Use a version of the BO2 combat knife, where it has to be equipped before being used, this would appease those who like to run around knifing and add much more realism to the game.
22. I like the idea found in Red Orchestra 2, where upon being shot you lose functionality of the limb/area of the body that is shot. To counteract this you have to stop and heal yourself. This system should be incorporated into the COD series. Healthpacks should be included in the flash bang tier, if you select them you have the ability to heal a crippled limb, if you don't you will have mobility issues (inability to run, aim noticeably hindered) until you die. Taking a headshot that you somehow survive should leave you with a blurry/red screen and possibly ringing of the ears. If someone takes damage it should impact their performance, not magically disappear in a matter of seconds. This would make people think twice about rushing around like an idiot, more strategic game play would result.
I'm sure I forgot some things, but you get the idea.