It's a well known fact that users "usually" don't welcome with arms wide open the 10% afterlife tax... :)
The reason behind this measure is that
"we needed to add a dead penalty because players tried to attack very high level monsters and they returned until they finally kill the monsters ( after dying 5-10 times )."
"I invite you to [...] propose a better solution, that is not so aggresive and that avoids the above problem."
Well here are my two cents:
If I'm not wrong, the damage inflicted to a creature by every player is tracked so that the total experience points gained after killing the creature are shared between players proportionally to the damage everyone has caused to the creature.
My proposal is that if a player dies while trying to kill the creature, all the damage inflicted by her to the creature is regained by it (if the creature is still alive, of course).
This way, no matter how many times the player comes back, because the monster will be awaiting her with its HP intact and with gained XP as well. This should balance the sides out I think...
Now, one of the possible drawbacks is that if the player is teaming up in a party, her death will be in vain because the creature will regain all of the damage that dead player has caused to it.
On the other hand this could strengthen team spirit (that is, things can get really ugly when a partner suddenly dies...) :)
Ok, honestly, do you think it is a better solution or should we keep the 10% tax?
I don't know what the "10% afterlife tax" is, but so far when I die sometimes I lose some of my items, which really sucks. One suggestion might be to cut the max hp in half for a limited time like 5 minutes. That would make it so you wouldn't want to die, but not have permanent consequenses. With the problem that you are talking about this effect would be more beneficial if monsters slowly regained their life back. It only makes sense, if they are not fighting, but resting they should regain their strength.?.?
I suggest that instead of the 10% back the skills and xp points are cut to the last level advancement, that is, if for level x you needed 140 points and you have now 299, you get back to your 140. This way the character would be learning what he can deal with and would not be subjected to down-levelling, which I think is terribly discouraging. The skills would be also cut to the last advancement. For solving the monster-killing problem, I agree that the monsters should regain health, maybe the faster the higher their level. Also I would put some kind of health regaining on the characters, but this is a different thing.
Aditionally, I would also suggest that, when dying, the character looses ALL his non-quest items, at least weapons and armor. Combined with the above, I think that would discourage the monster-killing issue, and make people more careful. After all, one thing is coming back to life in the other corner of the world, but doing it also with all your things... I keep quest items because I think taking them off as well would make this too fastidious, if for example you make a mistake or it is not your fault (lagging) when you die.
Just some idea.
And in this context the life ring or emerald ring would make the weapon and armor losing just as it is, random losses, instead of complete loss. Additionally it could make you not loose all the experience cut down to previous level, but a half or so... That depending on how good the ring is meant to be or if there is other similar items to assign bonifications to.