Something needs to be done to make death a negative, something that should be avoided at all cost.

Make it progress or something

Single weakness: 3min weakness 50% Decrease in attack (That is fine)
Double weakness: Increase the weakness to like 5 mins
Triple Weakness: Increase the weakness to 8 mins and keep the cannot attack thing.

You can use The different level raise spells to lessen each of the effects.

atm someone dies, then they instantly start zerging again.... No one cares if they die, no one is careful, no one watches agro.... it is sorta just sad.

I really hope they are making the dungeons where if someone agros it wipes the whole group. You know make it where noobness will severely hurt the event.