Actually a lv 1 char with 1pts on all stat, unequipped, they got
0% atk 50% c.dmg
Once u get ur atk% at 50,c.dmg% at 50(default), adding another 10% atk/c.dmg will do the same dmg number.
Before rebalance, there is 2 kind of c.dmg multiplier (from CRT and equips/al) which is calculated separately. After rebalance there is only one kind of c.dmg (crt+equips/al).
U can raise ur c.dmg with stat by CRT (CRT/200)(200CRT=100% c.dmg). But u cant raise ur atk% by stat unless if its supported by some equips, idk which is that. Simply said CRT build got too high c.dmg%.
Adding another multiplier such as atk% or elemental% does gives better dmg performance. It doesnt mean this multiplier works 'better'than this.
Its like more kind of multiplier with equal/balanced ratio is better.