Rosa can have 944 MAG in Arena (before buffs) and can deal 4446 Damage with this attack on a magic unit{97 Faith, 30 SPR, 15% Magic Res} or 5329 Damage on a physical unit{50 Faith, 20 SPR, -15% Magic Res}. She can one-hit any unit except Rain or a buffed spellblade.
Glacial with 25% ice attack just about offsets penalties from either build to, apart from weapon and passive, seamlessly do both
I prefer no charge time and greater range of bow skills tho, especially on certain live pvp maps people don't move their ayaka far enough away, they usually just concede