I’ve mulled it over and I think I know why I’ve got a lot of conflicted feelings about Castelle now that I’ve actually played through 3.2 myself.
Castelle had an amazing storyline together but it felt… cut short, though considering Cas’s prophecy I think that’s intended. In a weirdly fitting way they have the opposite problem StelleFly does. Castorice and Stelle met and adventured and bonded together, but that eternal separation cut that ship down before we could get to the fluff. Meanwhile, Firefly and Stelle’s first meeting and start to their story are gone, along with Stelle’s memories of the Stellaron hunters. This leaves us the player with only the fluff of that first date in Penacony, and many have (Correctly!) said that StelleFly came out of nowhere. It DID, that’s the point. There’s no context of why Stelle’s in love with Firefly, because that context was deleted with her memories. That’s yet another reason I really think Castorice and Firefly are intended to be narrative foils; their stories complete each other’s.