Eh, I don't buy the minisun. For one it steals Tamamo's schtick, for another Medea's already got a bunch of more interesting stuff, for a third it feels like pulling something out of her ass.
She's already got a bunch of tricks, you don't need to make up new ones. That gravity magic she used to in the Herv vs Kojiro fight would've been way more practical and useful and more importantly already exists.
Also it was horribly inefficient, if she'd lasered from early on instead of wasting time prepping the minisun things could've ended quicker, she could've supported Cu vs Vlad, cleaned up the wyverns and pinned down Atalanta all at the same time because surprise surprise she can laser more than one thing at a time. Burning the forest was a secondary priority at most.
Like, it's it's somehow both Medea wanking and at the same time making her look dumb.
E: Ok on second thought I think the minisun was in HF if I'm remembering the movie correctly but that was at a far smaller scale and it's still not a good tactical move. Time is precious.
I don't remember Tamamo throwing around small suns at anyone ever, though admittedly I never played Extra so I have no idea. Nonetheless I don't think lasers would have been enough, especially since that would involve getting into a sniping duel
with an Archer. You don't beat Atalanta by playing at her game, and Atalanta only needs to know where Medea is to eventually blow her head off with a shot to the head. The only way to win that duel is to not to play, by forcing Atalanta to relocate massive distances by destroying all of her cover.
I don't think Medea could, or even
should, be able to use gravity magic at that range. Not to mention that laser spam does not have the fear effect that would force
every wyvern to flee, and lasering them all would take precious time
and leave her vulnerable to attack because she
also has to see what to laser in order
to laser it. Also, if she was in a position to support Cu vs Vlad she would be in a position to get her head blown off by Atalanta, or savaged by Carmilla.
Ultimately, what you suggest requires that Medea be out and about, putting herself at risk in order to
maybe do things a bit faster, while being that much more likely to get sniped by a catgirl with a bow. And her being up and about isn't an option, either. Medea's a Caster. She's
doing something in the cathedral, and is not at liberty to leave.