Seems like they're preparing a new part of Time Temple.

I actually thought that was more because of budget costs than actual sprite functionality. They've proven able to make huge bosses with multiple summons- think Big Balrog , Von Leon, et cetera. Big Balrog is consistent with his size in cutscenes.

Having a huge Shinsoo pop up from the Empress's summoning wouldn't be impossible to do graphically, either.

Then why didn't they do it? Why didn't they make a huge Shinsoo for the Empress fight? There's no reason as far as I know. Or better. My supposition was that it'd have been hard / taken too long to make a huge Shinsoo, but apparently you proved it wrong by mentioning huge bosses such as Von Leon. Still, if it's actually longer to do, they might have preferred taking the easy way with Empress, or might have had to do it for design reasons and whatnot.

Anyways, I still think it's Freud in the video. They might have just not paid enough attention for his dragon to be identical to Afrien, and, mistakingly used Mir for the concept art. It'd just make sense for them to show the fight with the Black Mage which happened before we see Mercedes and Afrien after being hit by the Black Mage.

I really like, though, how they're showing that they haven't forgotten about the plot, and how it feels like we're getting closer to the Black Magician himself.

Though, is that Temple of Time area in the screenshot in the first page referred to the past or.. an area yet-to-be-released, where we might find the Black Magician himself or.. more of his followers / his generals?