I think this is exactly the problem with this suggestion, and I'd say everyone I've seen heavily in favor of this is very much in the "good-at-pvp" camp.
Worse people being able to stay alive (while doing damage), being annoying, doing objectives gives them a place in fights, and makes them feel more impactful and have fun in conquest. If they have to choose between dying while doing damage or living while tickling the enemy, I feel like a lot of bad players will enjoy conquest much less.
Having carries on your team is already a huge deal, and I feel like PVP skill as it is already rewarding enough. Tilting the balance isn't necessarily a positive change. And I think you already will do less damage if you spam KB because you will inevitably get in less hits, if spamming KB was truly superior every carry would just not carry a non-KB sword.
Also, it will make people die more, even if they choose to forego dealing damage to spam KB - the enemy will take much less damage, and basically never have to pot, making it much harder to get a respite if a better player is chasing them (they will have to pause less because fewer refills, and for example, if they are low on pots in inventory while chasing you, if your KB hits deal good damage, they might have to give up the chase after X hits, while if it deals much less damage, they can keep chasing much longer). Overall I think this will do more harm than good for the server, and the motivation behind most people wanting KB nerfed to me feels very much like that better players get annoyed when they cannot kill worse players in a short amount of time.
I have seen this mindset / philosophy more and more recently and I simply do not understand it. I think Cryptite sees things from your point of view as well. I will never understand not wanting to fix or address broken mechanics because bad players can easily abuse those broken mechanics. I had a conversation with Cryptite a bit ago about AIing golems and he brought up the point of giving players who are not very good at PvP a role to play at conquest. I do agree it is important to consider but I think at a certain point this mindset just gets harmful. KB 2 in its current state on Loka is just broken. This is objectively the case. This mechanic was not designed by Mojang with Loka pot pvp in mind. The desync makes the hits look insane and there is no reasonable counter that isnt using it yourself. Like hyper already stated, there is no reason not to use it except "honor" or bragging rights or whatever you may call it. Alot of good players use KB 2 all the time to fight! There just is no reason not to because you can land 2 or 3 crits on someone and send them flying, from their POV the hits look extremely stupid and chances are they get sent off their pots. It is just a broken mechanic. It makes no sense that you can have a sword that sends people flying without some sort of tradeoff or drawback.
As for the whole vanilla server argument I have seen people use, it is simply not worth addressing. I do not see why we are supposed to respect a mechanic or preserve it because it is vanilla. Alot of vanilla mechanics suck, and Loka knows this. Lokas whole thing is the 33% damage boost and theres literally a tip telling you why they chose it ("so that people can die, ever"). Loka has a shield nerf and a crystal nerf, a bow boost nerf, etc.
The priority should always be to address fundamentally broken mechanics. Just because bad players can abuse them does not make the mechanic any less broken. If anything it is quite the contrary. How are people meant to improve if the server hesitates to address nonsensical crutch mechanics that are easy to abuse? Why would any of these players bother getting better, or
how could they get better if the server encourages them to rely on stupid mechanics?
For me the logic of the whole thing is simple. You have got your regular sharpness 5 swords, and you have KB 2 Sharpness 5. The KB 2 enchant adds a whole different element of gameplay with no tradeoff. That just should not be the case. I like this suggestion because
it does not actually do anything to the way the knockback enchantment itself works, that still works the same! Other suggestions wanted it disabled some places and enabled other places, some people wanted a cooldown etc. but I think a simple tradeoff is the best option. You want to send people flying with crazy desync reliant hits? Thats fine, but those wonky hits of yours will deal less damage. The enchant works all the same. Knock people off cliffs and trees, keep them away from you or away from a teammate, etc. but in order to gain the ability to send people flying like that you get hits that deal less damage. It sounds completely fair to me and it encourages genuine improvement at the game rather than relying on a singular crutch mechanic that was never designed with our gamemode in mind.
Besides, I think critics of suggestion should try to get the broader picture rather than focusing on the specifics. The details can be up to Loka, this suggestion (for me, atleast) is just asking for
some kind of nerf to KB swords in order to disincentivize abusing them. There was a time where this playstyle was only really used by a single dude, and the server was just fine. A KB nerf would not be the end of the world. The server and the people playing it were just fine before everyone abused this stupid mechanic 24/7 and it will be just fine when it is finally eventually addressed (hopefully soon, and as a result of this suggestion!)