Professions

What generally makes any RPG different from other games is its depth of professions you can pursue. From gathering to crafting, a robust and deep profession system can go a long way to keeping players around. 

I added my thoughts in this green text where relevant.

Paths for productive player profession progression - Say that five times fast!

Crafting and gathering, the building blocks of any RPG alongside loot and combat. I've admittedly gone back and forth on whether you have professions be account wide or character specific, so for now I've settled on a blend of both. The direction any individual game would take with Professions likely comes down to the design of other systems in the game (i.e. whether you have a focus on a single character, if your attention is more spread onto alts, or a blend of both). Regardless, the goals for Professions should be to provide the right incentives for players to engage with each other in a friendly and economic-healthy way, while providing choices to specialize your player-character in a field of your choosing.


Construction and Housing - Home, sweet home

Homes have an unique place in MMO games. You have really interesting systems like Runescape that allow for intricate buildings and can house all sorts of rooms and equipment, but you need to balance that with keeping people from isolating themselves. I've always liked the concept of a "building" progression system (I love Cities: Skylines for this reason!), but it needs to be remembered that you're in a shared world! I do think you should be able to escape and work on your own stuff at times, but I don't want to sacrifice that idea of "we're all in this together". With any housing system, it should be predominately focused on cosmetic systems, building consumables, and creating your own "corner" in the world.