Alright, so Camilla's Axe is out. 16 MT, grants +4 ATK and SPD when within two squares of a cavalry or flying ally, and can be refined. It has the unique refinement effect of granting +3 ATK and SPD to cavalry and flying allies within two squares, and it notably uses Camilla's Rose's Thorn icon.
Is it worth it over Brave Axe? Probably. Takes my Camilla's ATK and SPD from 44/36 to 52/41, which becomes 56/45 when the bonus is active (which should be literally always) even before Flier Emblem buffs and Swift Sparrow. And it gives +3 HP, putting her at a very solid 49.
This means Glacies is probably no longer viable on her, so I'll most likely swap it over to Glimmer given her bonkers attack. That'll be a problem for a handful of matchups, but mostly I think it won't make a huge difference.
After all changes she goes from a 193 arena score to a spicy 209, which makes her by far my highest-scoring unit.
Now the question is, do I also give my second Camilla, who's current running the Distant Counter Res-stacking build with a refined Slaying Axe+, a Camilla's Axe as well? Probably, right? Those bonuses are too big to pass up. And if I do I'm not sure if I give her the Res refinement or the team buff refinement. Stacking two team buffs seems pretty hot, even if it will bring her Res down by a ton.
Edit: Actually not sure Glimmer is a good fit for Camilla Prime. Anything she doesn't one-round kill without it probably doesn't take much extra damage from it. Probably should either be Iceberg so that it's charged after a round of combat or Moonbow which will make a bigger dent in anything she's not killing regardless. Although I could see an argument for Noontime or Sol.
Edit edit: Do specials care about stat modifications? That's something I've never been clear on. And if they do, which ones? Depending on how the math breaks down I guess Camilla's long-neglected native special of Dragon Fang might make sense. It would have to count combat buffs to be better than Iceberg and I don't think it does, but I haven't done any experiments or anything.