EDIT: updated with more info from this interview @ MMORPG.com.
I don't really know definite answers, but this is what I got from watching the Pax South announcement and reading the MMORPG interview.
- PVE Masteries. These are confirmed to be very much like the World Ability Points we get in WvW to unlock special skills there. Account based points are earned by doing stuff there. Examples from the announcment: hang gliding, learn languages, special combat abilities, collections (for precursors).
My thoughts: They explicitly said the combat abilities would be usable only in the new "Heart of Maguuma" region. Since they said "region", I'd expect these to work on several new PVE maps. Personally I expect this to be true of all of the HoT masteries.
Also, they are calling this a re-imagined progression system: an alternative to raising the level cap and grinding new gear. It maybe limited to one new region in this xpac, but I wouldn't be surprised to see other sets of region-specific masteries in the future.
- Profession Specializations. These are single, optional variant each class. Example: Ranger > staff-wielding Druid. It's not yet clear how this is unlocked. They did confirm in the MMORPG interview that once your unlock the specialization you can swap back and forth between Ranger and Druid when out of combat.
Some folks have said that the new specializations are simply a new weapon type per class. I think that's an oversimplification.
Colin's words (slightly paraphrased) "Rangers will be able to grow themselves to become a Druid. And when they do so, they will have available to them the staff weapon. When a ranger becomes a druid, they will have access to a new heal skill, a new elite skill, a new set of utility skills and new profession mechanics that fundamentally change the way the Ranger plays if they turn into a Druid."
Like Fog, I expect you'll need the xpac to unlock the specializations. Maybe it's as simple as needing to do unlock quests in the Heart of Maguuma region which is inaccesible without the xpac.
I also expect that you'd need the xpac to unlock creating a new Revenant character.
- Guild Halls. Can folks without the xpac visit these? No clue!
» Edited on: 2015-01-27 13:05:13