The problem lies at many parts that act together. And needs a solution that handles a lot of those cases.
And a few key aspects i noticed:
- No warning
- Too easily accidentaly triggered
While the strong hit can be desired, its instant kill is not. However, with a proper warning, that insta kill might be. So for that i might have a suggestion:
Chiten now instead of having a binary Kuzushi, Kuzushi now works based on stacks. And for example each stack reduces the effect of guard by 20%, capping at 5 (we can also do 3 stacks and 33%, or basicly any value with a fixed point for the ohko), When maxed, the player gets a highlight (to mark the guaranteed instant kill and help the SAM).
This means that in teamfights, you can now take some risks as instead of instantly having a full mark, you can watch the stacks you obtained. And yes, there will still be that binary point of 4 and 5 stacks, but it enables a newer player to for example take 3 as their treshold for care, instead of 4. It gives a progression of survival, while still involving a risk/reward situation, that can backfire.
And yes, you can be sure newer/bad players will die by this because they dont track the stacks. Which then is a l2p, but its one they can at least be hinted to, and learn track! As its no longer purely binary. It requires a bit more setup.
As a bonus effect, SAM now can also use this as a teamfight buff even without LB. Making guard weaker for everyone can still be a strong effect and on that offset the cheese strategy. And its a lot more likely to trigger in that case, as people wont be worried as quickly, and are a lot more likely to just take those 2 stacks.