A gangster-themed revival of “The Importance of Being Earnest” helmed by David Hyde Pierce, a world preem by scribe Katori Hall and a new Richard Nelson translation of “A Month in the Country” are among shows rounding out the 2012 slate at the Williamstown Theater Festival.Pierce’s take on the familiar Oscar Wilde comedy imagines the upper-crust protags as two mafia hoods who fall for a couple of molls. Show, which runs June 26-July 14, is the latest directing credit for thesp Pierce, whose also helmed a regional staging of new tuner, “It Shoulda Been You.” Hall’s “Whaddabloodclot!!!” (Aug. 8-19), is presented by WTF in association with Signature Theater Company, the Off Broadway troupe that this week preemed Hall’s “Hurt Village.” Comedy follows a rich New Yorker who, after a stroke, is afflicted with a rare condition that causes her to speak with a Jamaican accent. Also on the Williamstown sked is a Nelson-directed staging of Ivan Turgenev’s 19th century Russian comedy, “A Month in the Country” (Aug. 1-19), translated by Nelson, Richard Pevear and Larissa Volokhonsky. Plus there’s a revival of Neil Simon’s “Last of the Red Hot Lovers,” helmed by Jessica Stone. Shows joins a lineup that includes the preem of “Far From Heaven,” a musical version of the 2002 Todd Haynes pic that will topline Kelli O’Hara, as well as a new play by Lucy Boyle, “The Blue Deep,” directed by Bob Balaban and starring Blythe Danner. The fest’s annual free theater offering is a stage version of Sherlock Holmes story “The Valley of Fear,” adapted by Steve Lawson. The 2012 WTF runs June 26-Aug. 19, with one more show still to be announced.