So, which boss FATE might become an instance in SB?

First, it was the Odin FATE that became a trial in ARR, then it was Proto Ultima in Dun Scaith in HW, and now that SB is out, which FATE do you think might become or be part of an instance this time? My guess is the giant fox from the Foxy Lady FATE. Probably wouldn't make sense for Ixion to be one since we already get him as a mount once we get 12 tokens.

The fox would make sense to reappear later, but one of the named Fox spirits is a key character in the AST quests, so that ship may have sailed. Though she uses a modified Fenrir model, so maybe not.

Odin only became a trial because of his FATE's unique mechanic (that the next time he spawned was stronger than the last the more he was defeated), plus lore wise he's a Primal so it makes sense for him to be a trial battle.

Behemoth never became a trial battle though, nor did any of the super elite Heavensward FATEs (like Courelregina and Proto-Ultima), so I don't expect the Stormblood ones to be any different really (although that last one does show up later in a raid, so anything's possible I guess).

And to be fair, Proto-Ultima never attended his own FATE. He just flew about for a bit and then disappeared, leaving the Rafflesia clone (technically already an instance) as the boss.

Ultima just felt like they patched in a trash pull that they hadn't completed on release....Odin deserves much more respect than being a FATE/Glamour boss.

The obvious choice would be ixion, he has a fair amount of mechanics you can never see because the zone is always so crowded, an 8 man version would be fun.