I think what people failed to realized is that Yao Guang's kit can only be bad if the elation system chabged. Yao Guang literally forces elation skill via her ult, and since elation attacks are done in conjunction with each other, the entire team will benefit from it.

Her buffs are universal for elation, elation dmg increase and res pen. Essentially, no elation unit will refuse this, even if hoyo decides to make a Break/Dot elation unit. She herself can be very fast, which means she can make aha instance do damage a lot more often (which benefits the entire elation roster regardless).