While I think Paddy Considine is a great actor and certainly did what the part requires, he also blended into the ensemble. His character is on stage quite a bit but doesn't really have flashy speeches that would bring him forward. A case could certainly be made that all of the actors should be nominated for Featured roles rather than Leading ones.
Laura Donnelly made a much larger impression on me than Considine did. Although she's not going to win any of the season's awards over Elaine May (or potentially Glenda Jackson), she is definitely giving an award-worthy performance.