Limitations will probably be the type of all skills, A / B / C / weapon (probably not, unless splitting available weapons by color is enough) / support / passive, and the availability being limited by star ranking is likely to remain no matter what. Someone would have to comb through the characters so far to list the skills of each type to see if there's any combination that's too OP. Stuff like "changing the color advantage", "double range" and "effective against armored / flying / horse units" would be the most interesting to build up your specific waifu but we'll see if that's included. Beside those advantages, I don't know if there's any specific skill that's too broken.
If I struggled to the end of my determination, to the end of my way of life with my followers, if the result is ruin, then this ruin is inevitable. Grieve. Shed tears. But you cannot regret.