I think the new Knockout has *potential* to be a good perk, but the numbers are tuned too low
First of all: I think the idea here is incredibly unique and extremely needed. A perk that targets pre-dropping and running away is interesting, and it's a cool and creative way to build a new chase-oriented perk for the Killer.
The issue is that the numbers are too low. Just SLIGHTLY too low. 6% hinder for 6 seconds would already make the perk significantly better.
In its current state, it *does* accomplish the task of making Knockout a healthier perk for the game overall than it is in its current state, however this is slightly too weak. The numbers are a tiny bit too low.
The name also doesn't fit the effect anymore, which is a problem, but then again it is likely to change since it's PTB and the devs probably know this already.

Comments
I like this concept for the perk and think it will really help M1s in chase, I really appreciate using Hindered and Haste as these are more dynamic effects.
However I want to suggest a change in that this activates with a cooldown ANY TIME a Survivor lingers around a pallet at all for more than 6 seconds, not after stunning. Stunning is really enough as a tool of deterrence and it does require a little bit of skill to pull off smartly, and should be rewarded. But the issue is some Survivors will try to specifically set up stuns or will hover around strong pallets or God pallets against weaker Killers, which doesn't have a lot of counterplay for these Killers.
Changing it to a Hinder effect while near a pallet for too long will better punish excessive pallet save setups, blinds after a stun (overkill and not needed, we all know you're just doing it for points or to be annoying), certain techs some Killers cannot otherwise counter, people who hover around a strong tile against M1s because they know the Killer can't get there, etc. Tiles should not be safe spots or get out of down free spots, you're supposed to run them not sit at them for stun/save points because you know the Killer cannot get there. Predropping isn't as much a frustration issue for M1s as these other things are but this will also help against predrops.
Just Leave the damn pallet and run the damn tile, that's what everyone here finds fun, not trying to help you get your stun challenge done, Meg.