I'm all for getting rid of the EXP Penalty as well. I mean, look at the math right now: At level 99, when you have a banked 55,999 EXP, and and loose a whole 600 EXP from death before any raises, it means you can die a massive 139 times before you ever de-level. And that assumes you do nothing or kill anything that gives any amount of EXP between those deaths, and if you're dying in a group, you probably are going to always have a Raise avaialble, and even if you're not in a group, the game practically throws Re-Raise 3 at you wherever you go.
Now ask yourself: Who would actually end up dieing that many times to de-level? Really the EXP loss is just a cumbersome affect to people leveling now, when the possibility of de-leveling is (slightly) higher than at the level cap. I say just get rid of the EXP penalty all together, and just go with Matsui's idea of having the various Raise levels lower the length of Weakness should be you be raised on the battlefield. Obviously there probably shouldn't be any penalty for returning to your home point, since you know...having to walk back is kind of a penalty in and of it's self.
Really, there's just no point to EXP loss on death anymore. When EXP was a precious commodity, sure, it made sense. Now, though, when EXP rains down from the heavens, showering you in it's EXP-y goodness, it's really just a slight inconvenience now than anything, and it's probably more of an intimidation factor to newer players than it is anything else. So axe the EXP loss, and just have Weakness be the penalty for being raised on the battlefield.