What is the difference between what is required of zone loads, and player loads. And why is it "required"?

Its only necessary if you limit the amount of ram your game uses to be a lot less then the total of all textures in the game. Also with proper organization you can load things sequentially even if most of the seeks are random. Wouldn't you load all of a spicfic set of say T4 armor and not just the bracers? Or are you of the opinion that loads are of each spicific item that is visible only? Do they load just the visible range or the visible range and say 40 yards beyond? Do they load all of the NPC textures in a zone when they load the zone or are they requried to do something else? If they load all the npc textures when you zone they why not load all the player textures of everyone currently in the zone also?

Fear loads the whole zone and I would assume character textures are well.

Well I guess WoW has a lot more character textures then what I would have thought. Would be interesting to see how much of the data files are character textures as vs. other information.