I don’t get why he get’s all that hate. Indeed he’s a strong merc but also a really situational merc which get’s better the better his team is.
I played like 20 rounds as, with and against him now.
On defense he’s perfect to flank the enemy push and pick off the medics and range mercs while his team distracts the rest.
On Offense he sneaks behind the enemy line and kills their snipers oder other key defense mercs while those are focused on the push.
But if you want to do something apart from these tactics you’ll have a hard time. Without chopper the only mercs he can onehit are Aura and Sparks and those mercs are designed so they can’t take that much damage. And Phantom isn’t the only one who can onehit those. Every Merc can do that with the good old stiletto. His armor sounds OP on paper, yes. But on the battlefield the energy is depleted really fast. One random explosion or a few lucky shots and the shild ist gone and mostly a huge chunk of his life too. And you won’t encounter hims with a full freshly activated armor most of the time. With that gone. He’s just a 120hp (mostly less) merc with a SMG and a buffed cricket bat.
His invisibility isn’t that strong as well. Most of the time I can the other Phantoms pretty well if you compare it to other games with this kind of ability (like Blacklight Retribution, Team Fortress 2, Ghost Recon Online, Halo Reach aso).
Let’s compare him with the TF2 spy for a moment.
Spy
- Onehits everyone (from the back and sides, sometimes facestabs)
- No delay between Stabs
- Completly invisible or even fake his death
- Can change his model to blend into the enemy team
- Can equip a powerfull pocket sniper revolver
Phantom
- Onehits two classes (but can hit multiple targets at once)
- Huge delay between swings
- not completely invisible, but get’s an extra shield which uses his cloak
- Has a SMG
The Spy looks waaay more annoying and frustrating to me.
But back to Dirty Bomb.
Since he can’t onehit most of the mercs and there’s a huge delay between swings the enemy has time to react to him. Full life Proxy for example. Phantom hits her from the back or the side. She survives, turns around and gives him a shotgun round in the face. No more Phantom. Happend a lot to me.
Every weapon has it’s range where it’s awesome. Yeah, his Katana ist the best melee weapon, but it’s kind of his second ability. But a heavy stiletto attack is also really strong and we all know how good those shotguns are at close range.
And take Vassili. He sits in the las corner of the map, hardscoping that one corner the attackers have to pass and headshots people. Onehit, insta gib across the map. If he’s lucke a double, tripple or even quad kill due to bullet penetration. Phantom on the other hand has to make his way to you and take his 1+ swing(s) to get you down leaving him behind enemy lines (maybe even wounded) with a (short) cooldown on his ability. So what makes him so much more OP then other mercs.
If I fight a Rhino it takes 3 swings to kill him. Should be enough time to turn around and riddle me with bullets instanly.
Fletchers panic sticky all over the place, killing off my shield and then onehitting me with a shotgun while jumping backwards.
Mines can still deal a huge chunk of dmg and alert every one in range to finish me off.
Airstrikes, Atillery, Grenades, Lasers, LMGs and of course those damn suicide grenades. All those things deal with Phantoms as good as with any other merc.
He’s only over powered if you don’t open your eyes or playing the lone wolf and srsly: Don’t play a lone wolf in Dirty Bomb. Phantom is the hard way to learn that lesson. 
I can’t wait to get those juicy Disagrees and Dislike from all those Phantom haters who don’t want to make a post themselfs. Mmmmmm, gimme gimme gimme