What the title really means is this: What’s good the way it is, what’s bad like “I’m not using that”, and Dirty…OP or Broken essentially.
The Good
So far I’ve seen some really good things in this game that I think are balanced or a little bit stronger then balanced but not in the realms of “Nerf Hammer” worthy.
A lot of the weapons are balanced. (Not Shotguns) So I’m not going over that.
The Mercs that I believe that are in a good standing right now. (Note: I’m not counting bugs, those are not put into this game on purpose)
Bushwacker/Flechter/Fragger/Kira/Nader/Proxy/Rhino/Sawbones/Skyhammer/Vassili
All of them are pretty balanced imo. They all can do great stuff if played correctly and they can be dead weight if not.
The Bad
None of the weapons , I feel, are underpowered, they all have their quirks that makes them different from the other guns.
The Mercs that need a buff
Arty/Sparks
Arty is basicly Skyhammer, just without all the boom. Yes, he has his artillery strikes but at the end of the day, whatever Arty can do, Skyhammer can do better and plus Skyhammer is free. They either need to A) Increase the raduis of his artillery strike by a bit or B) Increase the Ammo his packs give out. Maybe give him more speed?
Sparks, she is my favorite character out of the Dirty Bomb cast, her background story is funny, she’s extremely fast, and she has REVIVR, a gun that can heal and kill. She’s like Vassili except she can heal and revive, but as of right now, she underperforms against other Medics, why? She has 2 secondaries; a Machine Pistol and a regular Pistol.
“What’s so bad about that? She has a Gun that like you said she can heal and kill with it.” That’s true but look at Rhino, Big guy doesn’t have a Machine Pistol as a Primary and neither does Nader, but they are not Medics, Sawbones and Aura both get something called “SMG’s and Shotguns” to play with, so when they get into a fight with no backup, they can fight and not die in 2 seconds, but if a person looks at Sparks funny, she falls over and has a heart attack.
She loses about 90% of the fights she gets into and most of the time she doesn’t even start them and not to mention she’s a primary target, for I don’t know, EVERYONE. I don’t know how many times I’ve been killed by another player who just bum rushed me while I had allies defending me and he gets the kill and the finish, of course he dies but guess what, the team just lost their own Medic for a Proxy or Nader on offense. She can’t defend herself against other medics because they beat her in both Range and Damage, She’s effective at long range but any other range she gets destroyed in because, to actually do damage with REVIVR, she needs to charge it up, and hit the person who is jumping off of walls like F***ing SpiderMan. They need to buff her, Give her Access to Smg’s or Heavy Pistols, she needs a bit more damage to survive fights against the other opponents. Increase the Charge Rate on REVIVR. Or increase her health but keep her speed.
The Dirty
Shotguns need a range nerf. They act as meduim range weapons instead of close range and if someone with one does get close to you, well you dead. And why do Medics have shotguns? So they can rush someone and kill them? That’s not their job.
Aura/Phantom
These two…THESE F***IN TWO!
First Aura, what makes her so strong? The fact she gets a shotgun and a healing station that heals insanly fast, can take a lot of bullets before blowing up and a low cooldown. I have 1v3’d people as her, I have held an objective by myself for 5 Minutes without back up, I have taken on a Rhino by myself and won. And you know what helped? The healing station, It heals insanely fast, so fast that you just need to get out of the fight for a second and suddenly you have full health. And if I can do all that stuff as Aura imagine if someone like Rhino or Fragger was benefiting from it Shivers.
Her healing station needs a nerf, A higher cooldown, a slower heal rate, and a longer planting time.
Now Phantom This guy is the complete opposite of what the Dirty Bombs Devs say 'bout Dirty Bomb. Don’t be a D*ck.
Well you’re being one if you choose this guy. 120 health, fast movement speed sense he always has his katana out, and not to mention he has armor that allows him to take so much damage or become invis, well shoot, WHY NOT BOTH! His katana is strong and it should stay that way, It can 1 shot squishy Mercs that’s fine, but If I can’t kill him why he’s invis then that’s just absurd, I don’t know how many times I saw him coming and was able to take away his Armor but to little to late. I’m a bloody freakin corpse on the ground covered in stab wounds. One time he killed me because I wouldn’t give him candy. 
His Armor and health need a nerf.