The big difference comes down to...
a.) death by player action (stupid maneuvers, bad tactics, epic battles, poor judgment)
b.) death by die roll (save or die, random crits, bad die rolls)
c.) death by DM (assassination while sleeping, dropping a moon on you, no-save, just-die effects)
d.) death by plot (akin to death by DM, but usually a more scripted out method with player consent)
We (almost) all agree a.) is acceptable, Player actions should have consequences or the game is pointless. Most people agree c.) is unfair and usually bad form. d.) is permissible within certain groups (usually because its joint with the player) but not always for everyone.
When you come down to it, b.) is the only controversial one. Some players/dms like the idea of random death happening by "gambling" (aka dice rolling) and thus keeping it is intregal to the game. Others dislike the idea of dice completely overriding the PC/DM's actions and that luck is as equal an element in the game as skill (when skill should be much more important than luck in that mindview).
At the end of the day, the only argument about PC death comes down to "should the dice be able to kill you even if you've done everything right?" If yes, you typically favor a harsher view of the RAW, but if you say no, you're more at home with action points/hero dice/dm fiat.
I'm not sure they can make a core-rule set that will appease both audiences though...