Hello,
I don't think anyone who's used it is a stranger to the high RNG of buying costume stone boxes for the stones we want. It's a very unsatisfying gamble that 1) costs a lot of Fashion Points and 2) the same currency is used for costumes. At the same time these stones are a very significant part of gearing up for both PVE and PVP. So, there's a constant demand for FP in general but little ways to ensure that you don't just sink a lot of them into stones you (and often others) don't need.
My suggestion to improve the system and make it fairer is to give us the option to buy the desired stones for a higher FP cost outright.
For example:
Top stone of our choice = 300FP
Mid stone of our choice= 300FP
Low stone of our choice = 300FP
1st Garment stone of our choice = 750 FP
2nd Garment stone of our choice = 2k FP
Effect stone of our choice = 1k FP
