A) What are you doing with a casket in your pew?
2) Isn't it a little late for the occupant to receive Communion?
I don't have a clear idea of what the layout of a "church in the round" is like, but maybe there's no real main aisle, just a bunch of spokes, and thus an awkwardness of how you move from "back to front" when half of the seating is way over on the other side of the altar.
I'd imagine there's a problem with the Veneration of the Cross on Good Friday, too. Come to think of it, it would make any kind of procession a little unfocused.
I'm all for ad orientem.