I'm Team Corsair and Team Time Mage
Personally I am hoping we still receive multiple jobs released for the 7.0 expansion (2 as they have been doing), but I could see us receiving only one new job due to the exponential development load that adding any additional jobs to our current job list must create for balancing for a new expansion release. I am rooting for Corsair and Time Mage specifically, and here's why:
Corsair as Melee DPS - Now that Dragoon has a buddy for its Maiming gear with Reaper, "obviously" we cannot leave Ninja all alone with their Scouting gear!! To make a 6th melee would then perfectly balance the DPS roles across melee and ranged (6 melee, 6 ranged (ignoring Blue Mage cause it's limited)). And after all the experiences in Limsa Lominsa and the Merlwyb hype we've had all throughout the MSQ and other quest lines, we're due an awesome pirate-aesthetic job (that doesn't then just turn into Ninja at level 30). Perhaps the best weapon(s) for this job could be a "blade and barrel(pistol)" combo, and leave it open-ended so it could include cutlasses, daggers, scimitars, etc. and pistols, blunderbusses, etc. Abilities could range aesthetically with bombs, grapples (for movement?), gadgets, poisons, even "grog" as a self buff, perhaps? The pistol and potential bomb and gadget abilities would mirror well the ranged abilities that Ninja has from its ninjutsus. And of course, it would have a vulnerability debuff for enemies similar to Ninja as well.
Time Mage as Magical Ranged DPS (as many in this thread have mentioned, YAY) - I think we also are due a new caster DPS, since we haven't seen a new caster DPS since Red Mage released in Stormblood, which by 7.0, will be three expansions prior! In previous Final Fantasy titles, Time Mage has held a supportive role, and I could see arguments for it to be either a DPS or a healer. However, as several so far have discussed, I think with the job changes that occurred in 6.0, completely removing DOT damage abilities from Summoner and minimizing the importance of DOT damage on Bard, we are now missing a token DOT damage job identity from our DPS job lineup. What better way to aesthetically use "damage over time" than with the use of time magic? And yes, I know there has been some "time magic" in Astrologian's kit, but much of it has been removed bit by bit since its initial release in 3.0, hasn't it? How very convenient, one might say. This job's weapon(s) could be a floating crystal "ball" or foci, or even a single wand with particular flourishes for casting (though I could see how this may conflict with certain existing White Mage and Black Mage weapons from ARR). Perhaps one of the job's signature abilities could be an "Inflict the Past" style ability, where, similar to Machinist's Wildfire, some amount of damage is compiled over an X second duration and then applied, based on however many Weaponskills are activated while the ability is active, except that it is affected by the entire party's applied Weaponskills during the active window.
Notable other potential jobs that I would not feel Too Terrible to see in place of these jobs that I've seen mentioned in this thread are Geomancer, Chemist, - especially Rune Fencer or Mystic Knight (Listen, I want this so badly too, I do, but my heart belongs to pirates and time magic first). And like some have commented already, I thought they would keep holding onto Beastmaster and Puppetmaster for potential limited jobs in the future. Also, perhaps there's even better ideas fresh to the FF series, such as Reaper and Astrologian were. Guess we'll just have to wait and see! :)