We've been over this topic, while it is a cool idea to have -- and I agree with the reasons to have it -- the cons outweigh the pros if implemented blindly.
Pros:
Players stay logged in for 10 seconds. (adjustable) Which, means that player should think before they logout. This will make it easier for PVPers to jump someone fairly and not have (literally) almost everyone they jump try to ninja log to avoid it. (I seriously think this is a major issue.. that said.)
Cons:
Noobs and people who logout like that, WILL rage about it, and it will cause a pretty big backlash, as others stated, mostly because they're probably going to get gang banged by a bunch of gang bangers who're meaner, tougher, and stronger than them.
People can logout not knowing they're about to die.
Mobs kill players who logged out occasionally.
Suggestion to implement properly:
IT should only affect players who have already entered combat recently, like a 5m timer saying you were in combat recently and cannot logout immediately.
This will still affect people leveling but seeing as how we have the dungeon system it will be much rarer. (Because they can be grinding or in other words doing something productive and be in combat then get jumped.) I see it working for those people.
Additionally; mobs shouldn't 1 shot the NPC versions of the player during that 10 second window, how you might if it was a pvp combat log.
I would also wager to discuss removing the insta-death from logging with the 10 second timer, given two more circumstances in mechanics:
1) Does the NPC get affected by knockback and/or
2) is it a statue?
If it is not affected by KB and works like a statue, we should remove the instant death from logging out, and make the timer 15 seconds.
If it is affected by KB and does not work like a statue, we should leave the instant death from logging out, and make the timer 10 seconds.
But, only if the rest of the above suggestion is considered mechanically speaking.
/discuss