Name a player without whom our season would have imploded. Gotta be Lucas. Our system (with and without Kenny) has required a DM who gets stuck in; our loss to West Ham came mostly because he was shattered after 5 games in 2 weeks, including an hour when Brazil only had 10 men. As he has improved so have our results, but without him we would not be joint 3rd on clean sheets.
The other players mentioned only really came good under Kenny - we only had 3 players in the first half of the season: Reina, Lucas, and Torres. So it has to be between Reina and Lucas, for me, and Reina had too many off games under Roy.