What will define success for Dia’s new Beacon home north of Manhattan? “Is this the kind of work that will bring in 100,000 visitors a year? That’s the number Dia hopes for. So does the State of New York and Beacon and its surrounding towns, which have chipped in $2.7 million toward the project so far and have visions of Guggenheim Bilbao dancing in their heads. Dia: Beacon offers some of the most potent art experiences to be found anywhere, in some of the most well-considered settings. But it was conceived largely to present difficult work for long durations in one space. And for much of what it offers, difficult is the word.”