This year’s films with seasoned stars (“please don’t say ‘veteran,’” Ian McKellen, a hale 76, implored during a recent fireside chat with the Bagger at his hotel suite) also largely depart from familiar narrative arcs, like wrestling with dementia. (An exception is “Mr. Holmes,” in which Mr. McKellen’s famous detective struggles with a failing mind.) They don’t reduce their characters to what have become antediluvian caricatures: wholly sweet, or sharp-tongued, or doddering or dotty. In this year’s batch, the characters have sex; smoke marijuana; flirt; curse a mean streak; and, in the case of “45 Years,” ache over fresh emotional wounds.