I'm a competitive FPS player at heart. I am in love with the old-school, arcadey shooters made by ID Software known as Quake and Doom (excluding Enemy Territory: Quake Wars as well as Doom 3).
Call of Duty, as well as other somewhat similar shooters like Battlefield, have sort of taken a chocolate dump on the FPS industry for various reasons.
Lets contrast Quake with Call of Duty.
•In Quake, the base movement speed is very fast. You can move fast in any direction and you can also shoot while being fast. This allows for a constant fast pace and a greater emphasis on strafing, which is randomizing various rapid side to side and diagnol movements to confuse your enemy and avoid getting shot. Strafing is a skill that takes a lot of reflex and concentration but is extremely effective if you master it. It also makes aiming at skilled players much, much harder.
•In Call of Duty the base movement speed is slow. If you want to have any speed, you have to sprint. You can only sprint forward and you cannot shoot while sprinting, taking away your ability to contribute much to gameplay. Side to side movement is slow, severely reducing the effectiveness and emphasis of strafing which the game could have. It also takes away a lot of skill because now the only way to possibly juke your enemy in a firefight is to prone, but once you do that it takes a while to get up, making you an easy target.
•In Quake there is an emphasis on map control, which is the act of securing all goodies that spawn on the map as well as controlling power positions. As stronger weapons and powerups spawn on the map, there will always be opposition when you're trying to get them, rewarding more skilled players with better equipment. It also encourages map memorization and it means it's possible to predict where enemies will be. You also have to to master trickjumps, exploits in the physics engine that allow you to navigate the map more effectively but require tons of practice, timing, and concentration. Also in Quake, your starting equipment is weak. You have to gear up in the battlefield as fast as you can, then battle. Nothing is handed to you at spawn.
•In Call of Duty, there's no structure whatsoever due to the lack of equipment that spawns on the map. Everythings just a mess of scrambled chaos. You don't have to memorize spawn times, and there's no trickjumping. Instead all weapons and items can simply be handed to you at spawn.
•In Quake, there's no reloading whatsoever. It's a good thing as if reloads are too long, they can break the pace. Picking up and swapping weapons is also instantaneous.
•In Call of Duty, reloads take forever. The game encourages you to hide in the middle of a battle as you replace your empty clip, rewarding p**** players who keep their distance and stay away from the action instead of those who are up close and personal and fight their enemies directly. It also serves as a major pace killer. Switching weapons may also take a while.
•In Quake, everyone's on an even playing field initially.
•In Call of Duty, there are perks which make players unbalanced to one another, allowing players abilities others don't have. You can't have all of the perks at once and many are either necessities all players should have anyway or are just cheap/overpowered.
•In Quake, weapons are usually balanced and are to be used in different situations, requiring extra strategy. Kill times are also slow, making it more about who has consistent aim instead of who shoots who first. 1sks are very rare, even with rockets (Q3A requires a direct hit on an unarmored target to kill).
•In Call of Duty, SMGs and especially Snipers overpower other primary weapons due to extremely fast kill times. SMGs have fast reload and fast ads times and Snipers are also easy to use at any range. All weapons kill in less than .5 seconds. Attachments further ruin balance. Pistols are underpowered secondaries.