The next wave of JP Arms Micron (TFPrime) toys are now out and reviews are popping up all over the place. Videos here and photos here.

AM-19 Gaia Unicron (appears to have 3 modes - bot, vehicle, volcano/head)
AM-20 Ironhide
AM-21 Arms Master Optimus Prime
AMW-11
AMW-12
AWM-13

Unicron is not likely to be released by Hasbro any time soon (if at all), while the Arms Master (Weaponizer) Optimus has an exclusive Matrix sword that is inspired by the one from the First 13. (considering that this is all part of the new "aligned" universe, it is likely to be that ancient relic)
Note that the Unicron is packed on its own... so the earlier mock-up of a 2-pack with Optimus may have been an early idea to reinforce the combiner gimmick, or could still be an upcoming exclusive somewhere.

Ironhide is also likely to be a JP exclusive, as Hasbro have released the mould as Kup, with no mention of it being redone as Ironhide.

Plus, the next three single-pack Microns are all just redecos that don't combine.


Time to go shopping...