Having played my share of assassins and i am not a great pker but i even manage a positive ratio. I think you underestimate your pk ability.

Sure Emperor powers helped you, nage waza, ground fighter but even without these you would have done well.

I agree throw + ground control is the key to the complaints (which don't seem to be going away any time soon)

Throw on its own is fine. It lags like trip doesn't do massive damage. Your solution of moving ground control to 42 is the key imho.

This will make a massive difference for non hero assassins. Suddenly throw isn't your first choice every time. Sure it will lag like trip and deal more damage but without getting ground control at level 24 it will not deal anywhere near as much damage and players will not land kills as easy by spamming throw. They will start using kicks and other skills more as they will need to deal more damage.

In its current state i doubt many will get nage waza + ground fighter but i would remove both of these. Removing these will prevent hero assassins from being as powerful in the future.

So move gt to 42
Remove nage waza
Remove ground fighter

These changes should bring assassins back down to earth.