@ fallenshadow000
People consider the knifing cheap because the "combat knife" held in the hands of the player without another weapon equipped actually has a longer reach than the standard "panic knife" a player has available when equipped with a weapon. I'm not sure if the combat knife lunge is a far reaching as in other COD games, but its absolutely longer than the standard melee attack. Also, the combat knife increases movement speed, so when that speed is combined with the pick 10 system, adding lightweight, ghost, ex con, dexterity, the competent knife only player is not only incredibly fast and agile but will also retain his/her knife lunge advantage over that of the ordinary player whose panic knife range is almost nonexistant when holding a gun.
Couple all that with the small maps and...
Is it cheap? I don't know. I'm on the fence. As UnicornViolet has pointed out, this is just a video game, complete with all kinds of video game decisions, so reality doesn't have alot of sway here. But, when someone can enter a room and quickly dispatch 2 other players with a combat knife while being riddled with bullets, its not really about reality vs game its about the cost effectiveness of the weapons in the game. If the knife is utterly superior within 10 meters, and even effective within say 20 meters (not because the lunge is that long but because of all the added perks the player with the knife is moving too quicly to be hit by most players) and nearly all the maps are small...
I've played against teams who only ballistic knife + concussion nade/shock and while they are killable, this playstyle, when employed by skilled players, often empties the lobbies rather quickly. Most people don't understand the difference between the 2 knives, nor will they make the leap in combining perks in several slots and forsaking a firearm altogether, so I don't think this is ever going to become extremely popular, but who knows.