It's always disappointing to see people giving a negative response to constructive criticism on the game. There are flaws with it, and it's valid to raise the issues that you have with the game.
Personally, I've played almost every CoD game, and most of the ones with online multiplayer. In this edition of the game, I find the main problems are:
The spawning system seems overly flawed, regardless of how many patches there seem to be addressing this issue. I've played TDM games where I've been spawned away from the rest of my team, and effectively three seconds or less away from my enemies. There has been dozens of instances in this game where I've spawned, taken three steps, turned a corner and been shot without even having a chance to do anything. Spawning ought to put you in a practical place; somewhere out of immediate harm's way that's as near as can be to the bulk of your teammates. If you're regularly spawned into areas with numerous enemies, and only one of you, you're dead already. The spawns do not make for an enjoyable experience of the game.
Latency issues. I've played CoD online since Modern Warfare. In that game, I was constantly on 1-bar and 2-bar connections. You had to lead shots to get a hit marker in my part of the world, because the vast majority of hosts were in the US. I just got out of a TDM game that felt, latency-wise, like the host was in Japan [I'm in Australia, and the latency between here and there is between 150ms to 250ms almost without exception]. I've heard talk of lag-compensation and such, but every Australian player in that game [there were about 6 or 7 from memory; most on mics] had a less-than enjoyable time because guard dogs would be a dozen strides away when seen, but then they would go straight into the killcam replay with little or no delay. Similarly, you'd see an enemy, then be dead before your screen even registered that the enemy fired at you. That doesn't make for an enjoyable experience of the game.
Weapon balance. For the last couple of CoD games, there has been an ADS delay on sniper rifles. Even if you have quickdraw and ready up, you're still subject to a delay when ADS. In prior games, as soon as the crosshairs for the scope came up, the bullet would go exactly where you tell it to go. In this game in particular, there's a delay of around 0.2 - 0.25 seconds of being ADS before the aiming mechanism will transfer from being in hip-fire mode, to being in ADS mode. Given that the assault rifles, particularly the MSBS, have high rates of fire and short time-to-kills, it makes for an unbalanced weapon setup when the MSBS has a shorter TTK than the USR's hip-fire to ADS delay time. This means that in addition to only having one shot with which to gamble on killing the enemy, you have to aim it perfectly on a spot of the enemy in order to get a one-hit kill at the same time as waiting out the delay for the hip-fire to ADS that happens with snipers.
Continuing on about the weapon balance. The assault rifles are, like in most CoD games, vastly superior to every other class of weapon in the game. Consistently, the SMGs lose out. Rare is the occasion where an SMG can outperform an AR in any other department than run speed. SMGs typically kick more and have a significantly shorter effective range than most ARs. In previous games, the shorter effective range was balanced by having a greater rate of fire and a relatively lower degree of kick considering the volume of fire. In the rare scenario where the SMG is king, it's only situationally related to particular areas of the map, most of the time, the AR dominates proceedings. Also in prior games, the LMGs used to have a uniform damage over range. Now, the LMG has no upside. It's still often four to six shots at long range with an LMG, the difference being your run speed is now that of a sloth, and your reloads as drawn out as a Peter Jackson trilogy.
Shotguns often require two or more shots to kill the enemy at short range, given the enormity of the hip-fire spread. You'd think that would mean you should ADS when using a shotgun. Not exactly. There is minimal, if any benefit to aiming down the sight with any shotgun, save the TAC-12. And that's pretty pointless, since the TAC-12 has the lowest overall damage per blast of any of the shotguns in the game. Translation? You need two shots to take down an enemy anyway, even though the ADS spread of the TAC-12 is supposed to be smaller. In summation of this particular topic, shotguns, even when aimed, are effectively a gamble on which of the 6 to 8 pellets will actually hit your opponent or not considering how wide the spread is.You're actually penalised the ADS time to aim a shotgun, with almost no benefit to accuracy in doing so. In addition, the slugs are occasionally ineffective in that I've got short range hitmarkers with the supposedly "deadly" solitary slug, but not scored a kill.
The Riot Shield is a watered down version of what it used to be in MW2. Riot Shielders in that game at least had the option of scavenging stun or flash grenades; now you get one, and two if you spend a perk point on the extra. Considering how poor the pistols are on their own or akimbo, without the same aim assist functionality they used to have, you might as well not equip a secondary at all. Also, the Riot Shield user can be shot on the very edges of his hitbox, especially near the feet even in the crouch position. The drawback of the riot shield is you don't have a primary weapon to kill the enemy. So the tradeoff is, when crouched you should be almost impossible to shoot the feet of if the shield itself is in fact covering your feet from front on. Otherwise, it's just a useless class. Failing that, allowing Riot Shielders to scavenge tactical grenades seems fair. They have no primary - they need SOMEthing other than a riot shield with holes in it as their only means of defense.
In summation of the weapon balance, the assault rifle is king. Snipers are gimped with ADS delay, SMGs are only situationally superior to ARs, and LMGs had their only upside [uniform damage at range] taken away from them. The riot shield is easily bypassed, shotguns often require two shots to kill at their supposedly effective range, and marksman rifles are kind of like an AR, except with generally larger zoom magnifications, and little incentive to use outside of long sightlines. Given that every marksman rifle is at least a two-shot kill, irrespective of range, you might as well use a sniper rifle to one-shot somebody. Waste of a class given that most of the ARs have single-shot modes and kill in two or three bullets; the same as marksman rifles.The weapon balance pretty much favours the assault rifle over all other classes, again.
Perk system. You've just taken the pro perks from previous games, and split them into separate perks now. What used to be Cold-Blooded Pro is now Blind-Eye, Incog and Off the Grid. One perk is now three separate perks, costing 8 perk points in total just to be off the myriad of tracking scopes and heat sensors that now invade every aspect of the game. Now Scavenger Pro is just scavenger, and fully loaded. Sleight of Hand Pro is now split up into two perks. In effect, you have to spend the same or more proportion of perk points to get half or less of the perks you want. This detracts from the enjoyment of the game.
Failing everything else, I'd be satisfied with fixing the spawns. God they're awful.