As we all know, in Diablo I & II Full Plate was Always superior to Hard Leather armor (assuming they have no mods). Full Plate would give you 500 def and Hard Leather would give you 200 def (those are just random numbers). The reason being is that the higher your defense is the higher chance to avoid attacks you have (didn't mean to sound like Yoda). This system is simply illogical. Why is it that the heavier and more encumbersome my armor is the more likely I am to avoid attacks?
Years back I played a game called Siege of Avalon (for those interested you can get it here: http://www.amazon.com/s/?ie=UTF8&keywords=siege+of+avalon&tag=yahhyd-20&index=aps&hvadid=18667965011&ref=pd_sl_3h3gaxalnc_b ) It's a "Diablo Clone" in a matter of speaking. Top-Down view, point and click movement, real time combat, etc, etc, etc. It's a very fun game in my opinion a bit slower than diablo but its got a nice story. Anyway back on topic One thing I always liked about the game is that your armor has 4 main modifiers: Defense, Armor, Stealth, Restriction.
I'm going to focus on The first two as I think the latter would not apply to D3. Defense works just like D1&2 Defense, its your chance to avoid attacks entirely, or to avoid the majority of the attack(I swing for your head you jump back avoiding decapitation, but still receive a nick on your cheek.) This was always higher on lighter items such as leather, cloth, light mail, etc. Armor was your ability to negate damage, i.e. having your armor absorbing the blow so you don't feel it. This was of course higher in plate armor, plate mail, scale mail etc. This can be done in one of two ways, either a number (you take 50 less damage from every attack) or a percentage (you take 50% less damage).
Now this isn't to say that you either have defense or armor, but there is a trade off. It'd work on 5 item class system. The classes would be:
Cloth: Rags, Robes, Quilted Armor. etc.
Leather: Light Leather, Studded Leather, Cuir bouilli, etc.
Mail: Chain Mail, Scale Mail, Ring Mail, etc.
Light Plate: Field Plate, Breast Plate, Plate Mail, etc.
Heavy Plate: Full Plate, Gothic Plate, Ancient Armor, etc.
-------------------------------------------------------------------------------------------------------
Cloth would have a ratio of 9 Defense : 1 Armor
Leather would have a ratio of 7 Defense : 3 Armor
Mail would have a ratio of 5 Defense : 5 Armor
Light Plate would have a ratio of 3 Defense : 7 Armor
Heavy Plate would have a ratio of 1 Defense : 9 Armor
Moving on I think a system like this would work really well in D3, one of its many benefits is well have more unique looking characters. Let me explain, in D2 everyone in the end game usually had some kind of plate armor, with this system in place well have some lvl 100 barbs wearing plate, others leather and some even cloth. Another benefit is closely related, Whats the point of making all of those armor models when only the plate will be used in the end game?
Anyway I may add more later but for now I'm done. What do yall think?