Implementing this for server kicks and high pink seems okay, but how do you prevent someone from combat logging by killing their router on purpose when they're in danger?

I bet only some people would have that idea, anyway, in a pvp situation you dont think about killing your router ;)

Additionally, who has to know that there is no despawn animation when killing router?

And the most guys are playing DayZ in a group with ts, they got a few more network applications running, and those applications have to be restarted again, so, they wouldnt think about killing their router

The devs made it to where your character stays for 30 seconds after logging to prevent combat logging and server hopping to sneak around behind the person or people trying to kill you to get the drop on them. So I doubt they will change it back to the instant log out. In fact I'm pretty sure it's impossible for a script to be written that could distinguish between a router crash and just logging out.

This is a game that used to see players bind Alt+F4 to their mouse buttons.
Players will absolutely abuse an instant log-out if you let them.

I was killed while I was driving a V3S and suffered an unfortunate lag-spike, and the server decided my ping was too high and the best course of action was to force my character to tuck and roll under the wheels of my truck...My ghillie suit, AUG, and my longest living 47hr character was lost.

A good programm script can distinguish between losing connection and logging out, DayZ is already doing it as you can see when someone loses connection, then a message appears that says "XX is losing connection.

This message doesnt appear when you log out, so it can distinguish

Not a good idea. People will lose their connection by killing the router or pulling the RJ45 out. Network failures are not so common anyways.