My god people, why don't you think things through and look at options before getting all pissed off about it. Here's a great way they could do it to satisfy everyone:
-First death = loss of SP + weakness. A portion (or even all) can be bought back using Gil or possibly Anima.
-Second death while still under weakness (or within a time frame) = Lose more SP + double weakness. Originally lost SP cannot be bought back.
-Third death (maybe not necessary) = Permanent loss of SP (no buyback), double weakness, loss of Anima.
And keep in mind, under this proposed system, you would not delevel... lowest you could go is 0 XP (with possible XP debt). Aion does a system similar to this and it works pretty darn well.