Why I am not a fan of Hexakill on Rift specifically
On Treeline, it can make the game really hectic, since you are doubling the number of players on the map.
On rift, it is a 20% increase in the player number, and since the 6th man most likely went toplane, most of the map is playing regular league for the laning phase.
That is not to say that rift shouldn't have it's own "playerswarm" gamemode.
Just scale it up.
go big or go home
10v10 bois
TENTAKILL HERE I COME