Trailer for S3 in JP
Nothing new was shown, even the last scene was already unveiled before.
Easiest call ever, incoming.
Blue Mage Fina grows in strength/abilities as Season 3 progresses, right? At some point in Season 3, through some sort of key story event (trauma, rage, sorrow/anger, whatever) or some revelation about the true nature of her being, Blue Mage Fina is going to be the first 8* unit.
The first hit is (almost) always free, and everyone gets her just for starting Season 3. In that way, she can serve as an introduction to the 8* meta, while easily being powercrept as the first unit there (see: Lightning).
The only question is where the deliniation line will be between units that cap at 7* and which will be allowed to reach 8*. Although it is possible that Alim would go back and similar to the 6-->7* upgrade period and update all the rainbows, I doubt it will happen. Too many ancient units, some of which had re-dos over the last 3+ years. I believe the clearest line that has been drawn to date in that regard is at the 3rd anniversary, where the styling of released units change. Everything released after that point, starting with CG Lightning (hrmm.....) is going to be eligible for the 8* upgrade.
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/tinfoil hat time on
Using that logic, that would provide a sound explanation why all of the S1 heroes (except Sakura and Nichol so far) got new versions of themselves for S3, all after the 3rd anniversary. Also, a curious coincidence (or not?), using that cut-off point, is that there would only be one Order that would make the cut.... Physalis. In that case, the story mode would be right.... she would be the strongest Order, after all.
But, then that would completely suck for units that fall "just" short of the cut-off point. Why would you look at that, there's two GLEX unit powerhouses that were just released that would fall just a single month short of the cut. What a twisted way to eventually "obsolete" these currently game-breaking units, as they'll be left in the dust as "only" extremely powerful 7* capped units.
/tinfoil hat time off