Over the last six seasons, each of the five AL East teams has won at least one division title. The Yankees (2011, 2012) are the only club with multiple division titles in the last six years. The days of the AL East being dominated by the Yankees and Red Sox are long gone. The other three teams are no longer pushovers.
For what it’s worth, the projections at FanGraphs have the five AL East teams all winning between 79-88 games in 2016, a gap of only nine wins. Baseball Prospectus has them all in the 75-87 win range.