How about implement some mechanics to encourage killers to leave the hook.
Tunneling and camping is THE issue for years.
Killers go for it because the difference between 4 and 3 is too big.
Bad killers also live with only 1k camping all the game.
How about implement some mechanics to encourage killers to leave the hook,
or even introduce some mechanics to eliminate camping.
Some ideas would be like this:
Make killers get some buff(ideally chase power),
every time a killer hooks different survivors.
This way killers won't fell that bad about the instant unhook after leaving.
If camping is still not fixed,
a hooked survivor being teleported to a random spot by the entity entering 2nd stage might be a solution.
Survivors still benefit from unhooking for 1 less stage, so survivors can choose to stick to gens when camping is spotted.(Killers can get buff extended or 1 more stack in this case to encourage unhooking more.)
These two mechanics combined encourage killers to start more chases or their buffs would be wasted.
The buffs from hooks also encourage survivors to play more safe instead of sticking to gen.
Making it take a few sec to start a gen would also add some layers to decision making for survivors.
(Killers take time to kick gen while survivor can start it instantly is not right imo)