An interesting statistic might be something like the average differential in rank between the highest cheating hand and the highest legal hand that can be made on each pull.
Hand of: 9H, 9H, 9H, 9D, 7S, 7C, 5S
Highest Cheating: 4-of-a-kind (rank 8)
Highest Legal: Two Pair (rank 3)
Differential: 5 ranks
Hand of: 9H, 9H, 9H, 9S, 9D, 7S, 7C
Highest Cheating: 5-of-a-kind (rank 10)
Highest Legal: Full House (rank 7)
Differential: 3 ranks
I'm not sure if just comparing the average cheatin' hand rank and the average legal hand rank would really give you an accurate differential. If for no other reason that hands which are legal when creating the highest possible hand rank would have no differential, but they still factor into those stats when doing a diff comparison they wouldn't.