http://dbd.game/killswitch
Anti-Tunneling: Stick & Carrot
Tunneling is currently a strong, viable tactic for killers as is quickly reduces the number of survivors.
However, tunneling is a constant complaint by the playerbase as it's not fun to have your hook hovered or patrolled, if not outright camped, by the killer who is waiting to re-hook you. It also aggravates those who play with friends as one friend in a party may be out for a large part of a game their friends are in, annoying the party of friends.
With the above, we'll assume that tunneling is something we wish to see less of in DbD. So why not motivate "hook variety" and punish "tunneling" ?
The Stick: if the survivor you hooked is the same as the survivor you last hooked, increase the time their current hook stage takes.
The Carrot: if the survivor you hook is not the same as the survivor you last hooked, decrease the time their current hook stage takes.
WIth these two effects, you could tweak the increase/decrease as two separate values (50% / 10%, 40% / 5%, etc.) to something that is fair but solid motivation for killers so that the most effective tactic is not tunneling.