Agent class was created in times I missed, when there were more room for solo plays in game. Agent meant to use different devices to avoid open combat, fighting less and collecting supplies more. But currently you can't just avoid fighting, and agent has many problems.
1) -large zombie population
In current game state zombies fill every narrow hall and room in 2-3 minutes. Agent can't just bypass them. Cliff climbing spots are usually dead zones for agents. Scout has surv missile and drones for checking, agent can only find other way if he knows about the danger. That's why agent needs to have reliable anti-infantry weapon.
2) Agent has weapon setup what can't really be medium and allow completing of most of his tasks. Every choice has weak spot, and it would be not an issue for most classes, but agent can only rely on himself.
Raid shotgun is pretty good for escorting classes. It's medium weight and chance to hit 3-6 enemies are useful. But solo class can't rely on random chances, he has no ally to shoot few times, and every enemy in melee range is deadly. It's not worst weapon for class, just not suited for him.
Uzi - pretty much must-have in case that you are not solo currently. Very cost unefficent, misses sometimes, but has big enough clip size to kill zombie groups. You know what you will be the first in list of supply spender when you pick it, but you will have some chances in fight against zombie groups what you can't avoid.
Silencer pistol - was good before, now can't really be a good choice in the world of hordes.
Personal pistol was a great weapon, it is not bad even now, but what use it has currently? It does similiar thing to machine gun, it's not bad vs everything, leaving other slot for utility weapon, but agent has no such weapon. If it was in primary slot, swapped with silencer, it would be understandable.
Combat pistol got buffed and fits agent not badly, weight could be lower imo for better kiting.
Hunting rifle makes you too slow, and is not good enough against special enemies to explain this choice. You need to be assisted to use this weapon's potential fully. With this weapon we are getting into next class problem.
They are just random deaths for agent. You can be great player, kite well and use 100% of Distraction ability, but if you face Webber alone, you die. Slowly with heavy armor, very soon with light. Titans in good positions make agents very poor, => same for their team. Mothers and Watchers are both agent pain bringers. To kill Watcher you need like 3 clips of HR ammo, or 5 of combat pistol's, and you need to kill constantly spawned zombies too. I won't even tell anything about Creepers, they just detect you from a far and you can't escape.
Last, but probably biggest problem, what can be only fixed with real rework of class:
4)Passive and main idea of class
Agent will always be hard to balance out in version he is currently. Reason for that is that game is getting balanced around teamplay, and agent is worst class in this aspect. You can't rely on ally, because you lose your bonus of loneless. Literally every other class encourages teamwork, and only as agent player your ability to cooperate isn't a sign of skill.
There are some ideas for rework:
Agent as Monster Hunter
Difference is that agent would collect supplies not just in regular way, but also when killing or assisting in killing special enemies, 8-10 supplies per enemy. What would it change:
Passive, what would also give Agent some buff when fighting against special enemies.
Weapons set would change
Distraction ability would get change to be more reliable, probably range and effect strength buff.
He would have ability working similiar to oxy mask to give temporary sneaking effects.
An ability to set up bio-detection traps, what work only against special enemies. They would deal high damage in area and root the enemy for few minutes, based on his strength, giving a signal to player. Another job to place few of those around core.
Supply detector would detect special enemies too, but only as spots and only in front of agent at some range.
Agent would get a side role. He would be able to have an escorter too.