I've also been wanting to address this topic for quite some time, but it seems that every time I bring something up on here, it just turns into a bash Blackhawk and his ideas session, so I typically don't even bother arguing anymore, but here's my two cents on the matter anyway....
So, these kits are definitely a cool idea, and a viable counter to, as you mentioned before Emp, the uber high parry skills on players here. I'm not gonna lie, I use them, so it's not like I want them to be removed or anything. But do they give anyone who has them on their bows an unfair advantage against someone who doesn't have them on their bows? Hell yes... Anyone who would deny that fact is a liar, or has no idea what their talking about, lol...
I agree, the property seems to be, for the lack of a better word, "bugged" to some extent. I agree that it just needs a little tweaking.
If you have 20% Parry Damage on your bow, shouldn't the weapon special (mortal, for example) only have a 20% chance of landing if it breaks through the parry, instead of a 100% chance? That would be a good first step.
Secondly, I also agree that there should be a timer between the time your mortal is removed and the next time you can become mortally wounded. As it stands, you can be mortalled literally the exact same time your remove curse goes off, or the mortal wears off naturally. And people are totally taking advantage of these bows for that purpose, effectively "dumbing-down" pvp standing there doing one move, over and over again(mortal, obviously), and making it not even fun for a lot of players who would otherwise be having a blast here... There were problems with mortal spammers on previous servers that I've played on that implemented a timer between mortal shots, and it worked out very well. It really helped to balance the problem. I want to say it was like 10 seconds, maybe even less, but it made a huge difference. Pvpers actually had to come up with tactics other than pressing mortal, mortal, mortal lol : P
On a side note, I really don't think enchanted apples even work here to remove mortal, honestly. Some people I've talked to in-game about it swear by them, but I've done testing on them numerous times, and they never removed mortal. I've seen the mortal wear off 1-2 seconds after I ate the apple, but never at the same time as eating it, but I'm pretty sure that was just the mortal wearing off naturally after time. Even if the delay wasn't 120, I don't think it would help, if they aren't working as intended. Might need to look into that again, but i'm 99% sure they don't even remove mortal like they're supposed to, but it sure would be nice if they did work, i'll agree with you there.
Edit: I just tested the apples again to remove mortal, and they sure don't work, as of Saturday 2/11/17.
On a second side-note, is it true that you can add parry damage kits to weapons other than bows??? That would be great, but every time I've gotten a kit to use, it's in the shape of a fletching kit, so I just assumed it only worked on bows, so I didn't even try it on an axe or anything. That would be really cool if they did work on axes and such... really