So many things to respond to ;)
First off, not everything is going to be for SP. Just like not everything is for realm play. And chances are, players are going to be a radically different level at any given point in the game depending on whether they're playing SP, MP, the skill level of the player, their play style, and what sort of build they're playing. Some players take on hell baal with their level 25 firebolt sorceress (it isn't as if he regenerates) [edit - i was thinking of diablo, probably not possible to hit baal at 25] and some players aren't comfortable facing him until their ww barb is level 88. Some players will never reach 85, and others will have a dozen (yeah, even in 1.10).
You're right in saying that the high magic damage has a much greater impact on PvP than on PvM. And that Sanctuary has no effect on PvP at all. I think what you might be missing is that each item is assigned attributes depending on a whole host of factors. Some attributes are assigned to give the item flavor (otherwise, why add light radius at all, especially on high level items?). Sometimes it's an attempt to boost an underused class or build (this is a dangerous move though). Sometimes it's to add another opton for increased variety. Sometimes it's because we have a fun property and it has to go somewhere. Each item fills a different role (or often, several roles, and sometimes no role at all).
Azurewrath doesn't match the shear damage output of a socketed cruel/evisceration (except vs. undead and phys. immunes). But it's very useable and it's extremely cool looking. For some people that makes it worthless, and for others, they'll level to 85 just so they can use it (and items like it).
At any rate, it wasn't designed as a "PvP only" item. No doubt its influence in that area will be significant, but that isn't the "aim".
And the level req? Sad to say, it's pretty arbitrary. We really don't have time to test each item in proper context, so some things just depend on the intuition of whoever made the item.
First off, not everything is going to be for SP. Just like not everything is for realm play. And chances are, players are going to be a radically different level at any given point in the game depending on whether they're playing SP, MP, the skill level of the player, their play style, and what sort of build they're playing. Some players take on hell baal with their level 25 firebolt sorceress (it isn't as if he regenerates) [edit - i was thinking of diablo, probably not possible to hit baal at 25] and some players aren't comfortable facing him until their ww barb is level 88. Some players will never reach 85, and others will have a dozen (yeah, even in 1.10).
You're right in saying that the high magic damage has a much greater impact on PvP than on PvM. And that Sanctuary has no effect on PvP at all. I think what you might be missing is that each item is assigned attributes depending on a whole host of factors. Some attributes are assigned to give the item flavor (otherwise, why add light radius at all, especially on high level items?). Sometimes it's an attempt to boost an underused class or build (this is a dangerous move though). Sometimes it's to add another opton for increased variety. Sometimes it's because we have a fun property and it has to go somewhere. Each item fills a different role (or often, several roles, and sometimes no role at all).
Azurewrath doesn't match the shear damage output of a socketed cruel/evisceration (except vs. undead and phys. immunes). But it's very useable and it's extremely cool looking. For some people that makes it worthless, and for others, they'll level to 85 just so they can use it (and items like it).
At any rate, it wasn't designed as a "PvP only" item. No doubt its influence in that area will be significant, but that isn't the "aim".
And the level req? Sad to say, it's pretty arbitrary. We really don't have time to test each item in proper context, so some things just depend on the intuition of whoever made the item.