I am not a fan of exiling all creatures. From my experience destroying and sending them to the graveyard opens up much more interesting plays.
And Descend won‘t add and creatures for your delirium.
Kirtar‘s wrath would get my vote.
We used gummibears, but after a few turns it was difficult to track what should have how many counters. There might have been some snack based causalities…
I like Genesis, a lot. Though it is too narrow and slow for cube imo. I play it in EDH and even there, in a deck centered on self mill and dredge, the three mana activation is too expensive most of the time.