Like 6... Which we have all seen before and it doesn't hurt unless you make it hurt.
Here are the ways:
Item Degradation/Money hit (No one cares)
Item Loss (Hurts)
XP Penalty (If you have a 97% res, no one cares)
XP Debt (No one cares)
Play time loss (Hurts as long as it is a long time but no one is going to go through that mundane shit any longer)
Nothing - (No one cares, obviously)
The only way to make death hurt in an MMORPG is to make it frustrating as shit for a player but they keep coming back for some reason. At the risk of losing the player. Here is a protip: No one is coming back to the mundane any more. In EQ people came back because it was a revolutionary game at a time without social media and wide spread connectivity with others any time/any place. That's all over. That's why the magic never comes back. The magic has morphed into Smartphones, Facebook, Facetime, Twitter and 24 hour media.
So yeah I would say go for broke. Time Loss, Item degredation/money sink, and XP Penalty all at once. I want to see the tears on the 5 people playing it on Twitch.