I just noticed this was gone last night. I know this was never reliable because it always depends on what you're doing at the current time, but I'm hoping this will come back (at least somewhere)
My MacBook Pro early 2013 15 inch retina no longer sleeps. Pmset showed pid 214(corestoraged): [0x00001151000185fb] 71:05:44 PreventUserIdleSystemSleep named: "com.apple.corestorage.corestoraged". It looks like there is a bug in FileVault in this beta.