Doesn't really bother me but thanks to the title I couldn't help but think about it.. so here is my idea to that: Each WEEK (or maybe even month) a hub is picked, the game informs you in some way that isn't too obtrusive (perhaps a cute mini-map icon or buff).
This chosen hub gains:
Free teleport
Weekly quests that grant a substantial select-able bonus: like a pile of all tomes (including end game), extra beast tribe quest tokens and rewards from them, increase drop rate for rare/ex items in epic echo content, etc), maybe general tokens to be spent on neat things like special dyes, mounts, token conversions (hunts), rare chance to earn a khole token that allows you to move one stamp to any location and other neat things on completion (like a buff that lasts 24 /played/ hours of free teleports, unlimited spring out of combat, etc)
Substantially faster porter services (the choco, falcon, things we almost never use)
Faster regen and larger rested exp pool
Slightly cheaper tax on the market board (for locations you're buying out of)
Players who are not the appropriate level for that hub will get a weekly quest to visit and interact with players, this will apply a buff onto them to gain pertinent benefits. Interactions will be cheering, repairing gear (for free), and other activities on npcs and players, when targeting players they get an actual buff (and so does the caster so it is not like "polish my shoes" type vibe).
If it goes well can add special NPCs and quests thematically relevant, like while Ul'dah is selected you can earn some nice ... 'miners' gear by completing a quest chain available during that period. Limsa may have special water buffs that cause you to move 200% faster in water.
Major downside is a new person showing up in a hub that is a bit lore unique. Can delay new areas for a while to prevent that a bit (new area isn't a hub for a few months). Alternatively always have one cycle from OG city states and house wards and then one modern, but that splitting across two at that point.. eh.. lol.
Then do that to the area they belong to too (like scaling rewards during that period, so a level 70 is leveling in south shroud- if they wanted). You know.. use the open world space for stuff XD.