Citing flaws in the process that cost it the Greater Boston casino license, Mohegan Sun today joined a Massachusetts Superior Court lawsuit against the Massachusetts Gaming Commission, which awarded the license to Wynn Resorts. The suit, filed earlier by the City of Revere and the union representing about 145 workers at the Suffolk Downs racetrack, alleges the commission “acted arbitrarily and capriciously, and abused discretion,” while also ignoring provisions of Massachusetts’ gaming law.