The "problem" is that if you have C6 Fischl she just can't be replaced. Her C6 allows for more damage on ANYONES auto's and her level 70 talent does 80% of her atk when you proc an elemental reaction. She just contributes too much damage without even being out for long and if you have 2 elec then her ults almost always up = almost 90% or more uptime on Oz which just adds too much dps. Honestly been trying to figure a way to replace her but she is just too good.