Increase character logout grace period

Hello,

Problem: The duration of which the character stays attackable after a logout is too short. I've encountered multiple people exploiting this

Solution Suggestion:
1. While in combat, auto-extend the duration of which the character stays attackable after a logout
2. Increase the duration of which the character stays attackable after a logout
3. While in combat, any logout triggers an auto-death

Context: When I tried to have fun (Lordaeron) and do world PvP in the level range of 30-75, quite often, people just logout instantly and their character vanish before I am able to kill them. Just recently, I tried to engage 2 people with heirlooms on my own level. I tagged both and kept them in combat, but after I was able to kill the first person, the second person vanished into nothing. This happened about 10-15 seconds after I engaged.
Needless to say, 2 level 80 soon patrolled the area coincidentally.
To be fair, I was playing a spec that has low dps, so it would have been impossible to kill both in a 15 second timeframe.
I really appreciate the fix to the pvp-clear-on-relog, but this issue is worth a look in my opinion.

Thanks for your time