With sharding and cross-realm in place there are opportunities for players to interact across a region. Constantly players are playing with players from across the expanse. It seems like a rarity to see players in the same zone as I am who are also on my realm.
Sharding and cross-realm work really well. This begs the question,: Why not go the rest of the way? Merge into one big connected realm (by region of course) and use sharding to manage the over and under populated realms.
This could bring back guilds as it makes it so players who make friends in a dungeon or BG (premade or random) can create a guild together and form lasting bonds through shared effort. (Thinking Firelands or ICC like legendaries.) It could infuse the premade competitive spirit by making group achievements more within reach. (Side Note: Guild Halls. Please and Thank You) Communities are great but they really don’t have their own identity and flair. There is no pageantry, or common guild bank, or achievements.
The economy would balance out and normalize with steady supply and demand. The new Auction House UI shows unique items as a single market value stack. This is very doable.
I can hear some concerns from players who want to keep their populations low. I say have a toggle in the UI that tells the server the player prefers low pop shards. You can lump all those single player players into their own worlds. If you did it for Garrisons you can do that here (Side Note: A toggle for people who prefer RP would be equally helpful and dissolve the difference between realms similar to war mode. This should assist in balancing populations while preserving the RPers experience.)
There are also the concerns of realm firsts. I think a Region first would be even cooler. Further you can compensate by having First 10,25,50,100 Achievements similar to how you handled cross realm fishing tournaments.
Point is, I think that LFG, Cross-Realm, and similar random region based systems opened a pandoras box that harmed community cohesion. I think we can undo that harm and do more good by going to the rest of the way and making us, for all practical purposes, one giant realm (by region)