Just a copy/paste from what I had posted elsewhere.
My personal desire for a WoW 2 would include...
A Guild island -- Be it oceanic or floating above Ley Lines in an appropriate location wouldn't really be an issue.
Customizable Player Housing with configurable locations such as the guild island or a residential sector in <insert major city here> Endgame exploration systems on unlocked planet(s) -- For example on Azeroth we would depart from <Major hub town X> for a set period of time which would unlock and fill in details of the oceanic travels. The raid could include items such as epic craft materials, finding land masses which would be announced and named after the guild and displayed on other maps if your guild is the first to find it on that realm.
-- Part two of the above. Any islands located could be explored and then developed for items such as Trade/Military/housing
-- Part three of the above. Protection of said island, those into PvP would have to protect it from opposing faction raiders, and if you haven't earned enough rep to hire primary faction guards it would be open world pvp with no ramifications to your rep for booting a different alliance guild off of it.
World development. Picture it, being able to start in Goldshire and through your actions/contributions see the hub town you're in slowly develop, starting by seeing facilities upgrading such as the Blacksmith getting a better hammer/forge/etc then the INN getting nicer, until you start seeing the building(s) and roads start to upgrade. Limits would have to be in place such as an individual can only affect small things, epic quests slightly bigger things, major improvements would require parties, and etc... than after a long while of no players contributing it the town would start to decay which would require at least a slow constant flow of people going through the town to keep it upgraded.
A faction player city. At Endgame raid areas have a new contested city crop up that starts as a few tents around a fire, but as more guilds congregate on the location it will build up naturally until resources start getting requested to build it bigger and protect it from horde/alliance raids. After the city builds up enough on both sides have it essentially look like a morphed ying/yang with the steemwheedle cartel inhabiting a big circular area between both cities control a DMZ while reaping massive profits off both sides.
-- Again the cit(y/ies) in question would upgrade/downgrade automatically depending on flow of people through the area and how much $$$ changes hands in shops/taxes in the cities.
Player Professions mattering - This would more be a RP item, but making it so you could spin up a dwarven smith and never once hitting a monster while hitting the max level through perfecting crafts. For example a normal marketed Short sword via a NPC vendor would be Grey or White in quality, but after some practice your character could pump out a Signed Legendary form of the weapon while using a fraction of the materials needed when you first started practicing the craft. After a certain milepoint messengers would deliver quests to you which could be...
-- City lord requesting you to open your own shop at area XYZ
-- Profession master looking to take on a new student allowing you to learn higher crafts
-- Profession apprentice looking for a teacher
-- This would allow you to mass produce items, or have pre-craft items created for you.
-- Profession bulk item request from Merchant Guild or other association such as the town guards, city lord, faction leader, etc
-- Profession Guild asking you to join them