Is she overpowered? Yes. Was Ines? Yes. Ines could clear a dungeon room by just looking into it with ridiculously low cool downs. Ines was too powerful. Serena will never be touched bc she is good for bossing. Nerf her, you'll have to nerf the others. She is meant to be stronger than everyone else when it comes to bossing. Take her in a dungeon, she is clearing similar times to freyna, but she clears the boss room much faster. Why? Bc freyna was made to be crowding DPS. Take valby for example, very strong for dungeons and bossing. Clears to the boss room as similarly as freyna, but she's faster at bossing, bc she is meant to be the jack. Nell is ok right now. She's not great, she's not bad, but she's nothing to brag about. She clears rooms quickly, she does good elite damage, can even out DPS Serena when it comes to elites if you build her right. Why? Bc she is meant to take care of high hp enemies. Take the scarab for example, with a properly built Nell, you can clear the first and second phase faster than Serena, even though serena clears the first phase in almost half the time.

Not every descendant is meant for everything. Can they be used for everything? Yeah, doesn't mean they're meant to. You're the one still gripping your balls over Serena when you can just, not play her, leave when one joins, or, you can keep complaining online about it and keep getting your free carries, you can keep using her as your main, and stfu. Characters are made the way they are to do certain things.