Also, I will refuse to play this game, regardless, if they have experience loss on death.
The previous two mmo's that I played before WoW were FFXI and Asheron's Call. FFXI had xp loss on death. Asheron's Call gave you a Vitae Penalty lowering your stats when you died and you had to get XP to remove the penalty (not to mention dropping 8-10 pieces of high value items in your pack). When I got to WoW, I was amazed about how little people cared about dying. The first time I walked into AV, I died like 25 times. Coming from a pretty hardcore pvp'er in AC where you'd die maybe once or twice a night at most, this was a strange concept. WoW really has trivialized a death penalty to more of an minor annoyance instead of something to actively avoid.

It really is a different game though. In WoW, so much relies on your level being 80 that having xp loss wouldn't work. Delevel to lvl 79 and you are naked since you don't meet the requirements for any of your raided gear. In FFXI and Asheron's Call, you never really "stop" gaining xp so it works better in that area. Also, their is less of a reliance on being max level in those games as opposed to WoW. "Raiding" in FFXI starts as early as lvl 65 (MaxLvl is 75) with some classes and the rest of the classes between 72 and 75. I'd imagine it's less of a problem now, but when I played, it wasn't common for people to have multiple max level characters.

Maybe I'm a little strange, but I think dying should hold more weight than it currently does in WoW. Throwing out some pocket change for an entire night of wiping in ulduar (~200g) is nothing, especially considering that I probably paid twice that on consumables alone.

They are taking a step in the right direction with the Coliseum though. Rewards being lowered based on the amount of times you wipe should make things more interesting.