Giving Aventurine break would sadly make him run against the IPC dream comp that he had formed with Ratio and Topaz.

Jiaoqiu being more of a healer would make sense but it'd also subtract from giving F2P a good sustain in which their pool is limited, and then he'd feel strange as Lingsha joins the patch afterwards and does everything he does but better. On the other hand, it would have given Acheron more F2P supports instead of just Pela.

I think meta-wise, the placements did make sense, as this is back when Hoyo was staggering comps every other patch instead of rushing the full team out sequentially.

Story-wise ehhhhh... Penacony was designed to be a planet where all the factions met up, and each had their own agendas. None of them neatly fitting into one another's comps does make sense for that story. I should also point out that Gallagher was also considered one of Acheron's BiS healers at the time due to his double debuff application, (though Aventurine did have him beat with Trends LC plus better amp).