Balancing != making every class able to kite/handle every specimen on their own.
I agree.
Balance is to make sure ALL classes have vulnerabilities and zeds they struggle to handle on their own so they are more or less forced into co-op.
OR
Make sure ALL classes have tools to deal with all zeds so they don't depend on others.
I'm a level 6 Commando and I wouldn't want to be able to handle FPs by myself. If every class could do this it would cease to be a co-op game and more of a "run around separately killing stuff" game. That is not the nature of KF.
I do agree with you.
However, currently there are a few classes that CAN handle all zeds on their own. A few classes that does not have any apparent weaknesses (such as Sharpshooter).
Either give them weaknesses so they can not solo all zeds on their own (yes please) or give the rest tools to deal with all zeds in the game as well (the community as a whole tend to reject nerfs and praise buffs)
I am sure the game as a whole would be better of if for example Sharpshooters didn't have access to M14EBR and that crossbow bolts didn't do this insane amount of damage to fleshpounds - before patch you needed two head shots and then some with a rank 5 sharpshooter to bring down a six player hard (or was it suicidal, don't remember right now) fleshpound (one to enrage them and one right before they start to charge) and about 5-6 bolts with a non-sharpshooter, after patch you need like one or two bolts as a non-sharpshooter to bring down a 6 player hard fleshpound with a crossbow (indirectly making all classes that have a 4kg perk weapon - such as demolitions using M79, Berserkers using Katana, Medics using MediSMG as well as support specs with shotgun, Katana and Crossbow - viable against all zeds in the game).
Before patch sharpshooter would shift between 9mm (for clots, bloats, stalkers and gorefasts) to deagle(s) for crawlers, stalkers, sirens and to panic stun gorefasts and scrakes - into crossbow to kill scrakes and fleshpounds (and lined up lesser zombies on open maps like london and farm). Running low on ammo in all three weapons at later levels. Struggle with swarms of zeds at close range as you sometimes don't really have time to head shot them all. Well balanced.
After patch i just run around with EBR killing everything, including FPs and Scrakes. Lots of ammo to spare. Ezmode, yes. Powerful, yes. Boring, yes. Balanced, no - would be if firebugs and commando perks could do it though.