We’ve been very critical of Groupon and its founding CEO Andrew Mason. The enigmatic Silicon Valley guy has famously shunned Google’s $6 billion bid for his company and seen his stocks fall to levels that make the shunning itself look downright ludicrous. We were critical when the shares were falling to $15. They’re hovering over $5 today. Still, should he be fired? A year and a quarter since going public, the company is in big trouble. Mason is fighting to keep his job, but just as Larry Page turned to Eric Schmidt to lead his company through the crucial years, should Groupon do the same? Investors…