Let's just brainstorm ideas. This means no evaluation of practicality, tradition or logic... a brainstorm in the truest sense. It may be tempting to write paragraphs, but being honest short and to the point is more likely to be read.
Next Expac:
-I'm hearing that serious raiders want another Underfoot. Deep tiers of raiding with worthwhile progression stages/itemization that is difficult to do in era.
-For years the more super-casual have been wanting another The Serpent's Spine. A reason to play 1-85 again. New quests. New race(s). Even the shortcut of new races out of a revamped Crescent Reach (with TSS quest gear being better than same level defiant) could pacify this interest somewhat. There's even a couple of easy to use races (Goblin, Sarnak, Aviak, Kobold) that it would be pretty easy to lore-stretch into PC races.
-No more continents. The world is massive, and unfinished in so many places... ripe for revamp in so many places.
-More race/class combos... even adding 1 a year (and sticking with the most logical such as Iksar Berzerkers, Erudite EVIL wizards, mages, etc. vs. doing goofy stuff like Dark Elf druids)... and allow them to start at own racial cities! (so fix wood elf beast and froglok monk...).
-continue AA and other consolidations to make returning to live 85 game more appealing to people that have been away or never played. This is a big deal, but hard to see if you've been playing all along or even just the last few years.
-Revamps... with logic. So don't change the zone geometry except maybe adding a tunnel off (for example) if adding a new zone (i.e., Deeper Kithicor could be made off of Kithicor forest). Progression servers are enhanced when zones are obsolete (i.e., Cazic Thule) and the live game has way too much under 80 content. Yes... they need to move or provide alternatives to quests NPC, but we don't need the massively diverse levelling tree of zones... in a post-PoK world you could make Lfay, Dagnor's, Unrest, etc. level 90+ ...might even improve retention of returning players if they were doing old zones for new loots in the 85+ game without this being a special event thing.
-Old stuff used in new stuff. Instead of complaining that Epic quests are too hard to write x 16 do more of what was done at times in the past of linking quests together (earring of Solstice, Updated Coldain Shawl, Cabilis class quests). Something like Breakdown in communication is already basically an epic... why not create a level 110 group quest upgrade to it and a 110 end-game raid upgrade? Get value out of the assets already in the game.
-Speaking of old things... re-use some old factions in fun ways. No more new factions ad naseum (or currencies)
-launch a new live server with the Phinigel server boxing code, instancing/load balancing but with at least normal XP. Allow paid transfers into this server. Consider giving this server (or doing 2) with the FV loot code but none of the other FV server pecularities.
-Do some live servers need merging? Maybe it is time to offer free transfers off the 2-3 lowest population ones and then merge them away leaving a few less original servers, but hopefully more robust.
-Some special servers do need merging. Vulak (I play there a bit) does. Trakanon currently has transfers off... but is pretty low population. I play there too. Vulak and Trakanon gone allows them to try other things (How about a no marketplace, no Krono, no loyalty, no claim server? --funny thing is I think people would sub to play on it).
-multiclassing. I don't know how to balance this... but it could be a fun way to extend the game. Maybe a special hotbar (like potion bar) that only lets you use 3 "off class" abilities at any given time with a noncombat memming requirement? I hesitate to do it under the current AA system...