Well, it's Storm Legion now and we've defeated all six dragons, but yet we're only 60 levels and one expansion in, so there is still a lot of room left for expansions, which raises a lot of questions. After all, it seems highly unlikely that if a dragon god is killed their Rift plane is just stabilized, at least not forever.
Let's look at the established predecents for Rift's second expansion to start:
-It will include a new continent or two, or at least some new zones
-It will involve the rebirth of dragons and/or journeying into the planes through the Infinity Gate
-The level cap will be increased to 70, or perhaps 65
-The existing souls will gain new abilities
-It will probably be released sometime in 2014
Other than those assumptions we can pretty much take for granted, what does the future hold for us Ascended?
Theme?: There's been a lot of speculation about the planes themselves or other dimensions being new "continents" at some point, but I suspect that'll be later on. Instead, I think it's likely that we'll see Greenscale and Akylios return somehow more powerful than before as the bosses of the second expansion. Air & Death got their spotlight in Storm Legion, Fire & Earth got Infernal Dawn/Ember Isles, which leaves Life & Water. Although we have defeated them, the one Kelari at Ember Watch says "Have you heard the Aelfwar have got a new leader?" which hints they will be back. As for Akylios, remember all those Water Rifts and zone events in places like Ardent Domain and Seratos? The water invaders say things about how they will return someday - I doubt Trion would put all this in without a good reason.
New low level content?: I expect Trion will focus a little more on new lower level content this time, or at least make a new starting area. There might be a new Ascension storyline for Guardians and Defiants or even a new neutral race that can side with either faction - just like the Pandaren from WoW. The old Mathosia zones will probably also be revamped at some point.
New souls?: My answer to this is a resounding "yes". Once Trion makes one set of new souls available it naturally follows that more will be forthcoming in future expansions. Players expect it. If Trion were to stop creating souls it would make the Storm Legion souls seem rather awkward and out of place. Note that I wouldn't expect Trion to offer new souls with each expansion, but I think 10 souls for each calling seems like a nice round number to me.
Expect the new souls the tie in with the lore of the next expansion. Here are just a few ideas for souls that would fit well into a Life and Water theme:
-A soul that draws on the power of the four seasons (the seasons are a big part of the Plane of Life as well as world events already and I've always felt a season-themed soul would fit Rift's theme very nicely, especially Clerics)
-A Water Mage soul that pairs well with Stormcaller
-A Pirate-themed Rogue soul
-A shapeshifting soul
-A woodsman/lumberjack type soul
Another thing is the Storm Legion souls were all DPS and/or Healing types so I think it's likely that at least one of the new souls will be a new Tanking soul.
Wishlist - things I would LIKE to see in the next expansion, or future
-If and when Akylios does return, I would really like to see a seafaring themed continent full of islands, pirates, deep ones, and Abyssal cultists, and maybe a Vashjir-style underwater zone or two.
-Planar attunement needs more expanding with the recent account-wide changes and XP nerfs. Many if not most people have all seven maxed out now and Tier 3 won't provide that many more levels. I really think they need some bonus abilities for each plane that are simply "fun", and wouldn't influence a purely pragmatic raider. For instnce throw in some things like cosemetic Ascended Powers or even a Dimension themed around that element and some (now that would be awesome) and players would have more things to look forward to and choose from, especially if the bonus attributes end up costing more levels
-I'd like to see more lore on the Conquest factions and how they came into being. Maybe we could do daily quests for our favorite one and gain favor through PvE as well as PvP dailies in 3-way Aldor-Scryers fashion (gain rep with one, you lose rep with the other two). This would give players reasons to fight for the one they agree with lorewise. A couple more Conquest maps wouldn't hurt either.
-Going up to 71 soul points for each soul might be a little too much, it might be time to narrow down the soul trees a little. But I REALLY hope Trion NEVER does what Blizzard did with Mists and keeps the soul tree system instead of just giving us abilities...