Guild Wars 2

Each Region (Ascalon • Kryta • Maguuma Jungle • Shiverpeak Mountains) has about 6 zones which is perfect as there are 6 armor slots.

My suggestion is to add an armor smith for each region who requires items found in each of the zones for a certain piece of armor be it from kills, exploring to gathering. Very it up and make it challenging not something you can just buy.

An example:

Ascalon

Items in Plains of Ashford go towards building headgear.
Diessa Plateau – Shoulders
Fields of Ruin – Chest
Blazeridge Steppes – Gloves
Iron Marches – Leggings
Fireheart Rise – Boots

As a bonus it will bring people to these zones.

Perhaps even items to make the pieces are found only in the various regions with the smith found in the highest. Visiting them lets you know what they need from various locals around different maps.

Would be a great way to get people back in lower zones and a great way to continually add new Armor to the game