I know I'm a few days late with this comment, but am i the only one who thought the murdering in plain sight trial was a little unfair this year?
They revealed someone was poisoned, so most people immediately knew it would be via a drink. With Diane having a slow death, she and others were able to tell the group exactly who gave them drinks the night before. And the chalice wasn't exactly inconspicuous.
If Diane had been murdered immediately, she would not have been able to tell anyone who gave her a drink, it would have been up to everyone else to guess/remember who had given her one.
With this very obvious task, and the slow poisoning, the producers gave them a traitor (Miles) on a plate. The murder in plain sight last year was far more subtle.