Latics wowed the nation with their run to an FA Cup fifth-round reply loss at Everton having memorably dispatched their conqueror's Merseyside rivals Liverpool to reach the last-16.
However, deteriorating form in npower League One saw boss Paul Dickov pay with his job before rookie Lee Johnson led an ultimately successful fight against relegation during the closing weeks of the season.
Former Huddersfield forward Simpson made 44 appearances for the Boundary Park outfit but was released at the end of the season, albeit with a glowing public reference from Johnson.
"It's a tough one," he told Press Association Sport. "Obviously we went into the start of the season full of hope that we'd surprise a few people.
"We were one of the favourites to go down at the start of the season but I felt there was a real belief, especially in pre-season, that we could challenge at the other end of the table.
"But it wasn't to be and consistency was our issue. That was proven in our cup run. In the FA Cup we had a great run, beating the likes of Liverpool and then drawing with Everton. Forest away and Doncaster, who went up - we beat them as well.
"In those games we showed we had the potential to challenge at the other end of the table if we could perform like that on a consistent basis. Other than the cup run you'd say it was a bit of a disappointing season but that cup run seems to mask a lot of things."
And Simpson joked that the season was an ideal one in many ways for Oldham chairman Simon Corney.
"If you look at it from the chairman's point of view he's probably delighted," he said. "He hasn't had to pay many win bonuses but he's got over a million (pounds) from the cup run."