Suggestions To Make Kayn's Ult More Unique
Rhaast form While inside an enemy, can re-cast R on another enemy to jump to them (like in the reveal trailer).*
Kayn form Upon exiting the enemy, E has a longer duration and higher movement speed. This would give the assassin form a way to get in and get out after killing the back line.
*EDIT: Jump TO them not jump inside them.