Hear me out before you yell at me "peacekeeper op peacekeeper op how dare you say she needs a buff".
Quick information: yes i main peacekeeper, i got her up to rep 2 lvl 13 at the moment i am writing this and no i do not want them buffed because of that reason, like i said hear me out please.
So first off i mean parrying, not deflecting, deflecting seems fine.
The problem that peacekeeper has when parrying is that she can make absolutely no benefit out of doign so, her attack range is too short on quick attacks and her windup on heavy attacks too long so she can't attack anyone after parrying.
The only thing a Peacekeeper can do after parrying is to go for a guardbreak, which is not allways possible when the enemy is farther away either though, meaning that you get nothing out of it.
My suggestion would be to change for Peacekeeper (and maybe every assassin) that the parry moves the enemy closer towards you, instead of pushing them away. With this change assassins would have an easier time sticking to their target, and the Peacekeeper can actually make use of parrying in the first place, instead of only depleting a portion of the enemy stamina.
Now that that part is out of the way here comes my oppinion on her balance wise.
I don't think she needs any buffs or nerfs other than the said parrying buff because like i said she is the only character (maybe with the berserker, not sure) that can't benefit from parrying.
First off: attack speed) people seem to think that her attackspeed would be faster that that of other characters but it is not, whenever i initiate an attack at the same moment for example the nobushi or kensei do we will end up trading, and the warden upper attack comes out even faster than my light attacks.
2. the "op" bleed on guard break: is it alot of dmg? yes. but you have to keep in mind it's a bleed, so you can make use of that health and don't loose it instantly like for example the kensei unbreakable dmg does which is the same dmg or even more (and i don't see anyone crying about that).
Her deflect that inflicts bleed basicly does combined with stab+bleed as much dmg as the orochi deflect does so that is completely fine imo.
Now to the part that the peacekeeper has the most problems with: attack range and tracking. the peacekeeper is probably the only class where a simple dodge to the side will get you out of most attacks cause her attackrange is very short, and she dosn't have any tracking other than the wide swings on her heavy standing attacks.
Basicly as soon as the enemy knows how to parry a guard break and block or even parry you, you will have alot of problems as peacekeeper due to the fact that you don't really have alot of benefits going for you and can't use parries either.
Like i said the only change i feel necessary to this class would be making parrying a viable tool, otherwise her dmg mobility and speed seem to be fair compared to other assassins.