Given that the next expansion focuses on the Delta Quadrant and Cryptic tends to focus on logical, systematic game design, we can make a few educated guesses. Here's my guess.
The new ship class will be some form of Explorer, a classs of ship specially designed for extreme deep space range exploration. Independent, Robust, armed for both scientific research and combat. It will be some form of cruiser/science vessel hybrid with better hull and more weapon slots than current science vessels and yet still able to use a secondary deflector but lacks (or only has partial) access to beam targeting and sensor analysis.
With regards to Tier 6 ships, basic tier 6 ships (the standard 3 cruiser, escort, science vessel we get at each tier) will be available for purchase at ESD, Qo'nos and New Romulus. It is likely that all gold players (players who have spent money) will get a tier 6 ship token for a free upgrade to these basic tier 6 ships. Lockbox ship owners will buy upgraded variant of their ships from the dilithium store or lobi store. As for C-Store ships... I'm not certain what Cryptic would do. If Cryptic is kind, it would be as simple as buying a tier 6 ship upgrade token and viola! your current C-Store ship becomes a tier 6 ship. If Cryptic is unkind and greedy, they will slowly release new tier 6 variants of current C-Store ships over the next 2-3 years.
If there is going to be a new Fleet Holding, then my guess is it will be some form of Delta Quadrant outpost that come with its new set of fleet gear. Current fleet holdings will start selling Mk XIV fleet gear at higher prices and the Fleet shipyard will sell tier 6 fleet ships too. If there won't be a new fleet holding, then its likely all current fleet holdings will get a new tier which unlocks Mk XIV gear and tier 6 fleet ships.
Since there will be a new personal reputation faction, my guess is there won't be Mk XIV versions of current MACO, Omega Force, Romulan, Nukara, Dyson sets. This is the perfect chance for Crpytic to wipe the slate clean of the old overpowered sets and make us players work for new gear.
I have no idea what the new class of bridge officers will be. For a brief moment, I thought it might be MACO bridge officers, but it would be the wrong expansion to introduce them as they are not something from the Voyager series. Ship's counselor maybe?
