Differentiate Rek'Sai's ult
Currently Rek'Sai's ult feels a bit too similar to Nocturn's There are few differences between the two. One way this can be remedied would be to play into Rek'Sai's less developed theme: Being the Xer'Sai queen.
Update Rek'Sai's ult to cause small Xer'Sai to dash to the target champ from the Tunnels Rek'Sai has placed, and then dissapear back into the ground after converging. Only the targeted champ is dmg'd and the dmg can be increased for each Xer'Sai that hits. This will add reliability and more skill expression to Rek'Sai, as well as a bit more flavor to her ult.