It's an ESPN insider article. For those with access, it's a fairly good read. For those who don't have insider access, KC Joyner, known mostly for his NFL work, details O'Brien's move to Wisconsin and why Badger fans shouldn't expect O'Brien to be the next Russell Wilson. Specially, Joyner cites O'Brien's "woefully" poor mechanics and repeated errors under pressure. Surprisingly, Joyner also calls O'Brien out for what he calls poor leadership. According to Joyner, O'Brien repeatedly made "wild gestures" at his wide receivers when O'Brien thought they made an error or dropped a catch. Joyner even alludes that the Terps coaching staff may have went with Brown because of O'Brien's poor leadership and the fact that the team seemed to be more motivated to play with Brown under center.
I don't want to detail the mechanics aspect too much because I'm not sure what this blog's stance is on paywall articles -- but the amount of mechanical issues Joyner points out paints a quarterback that deserved to be benched last year. I know there is a large fan base that believes that Edsall ruined the next Boomer Esiason, but Joyner seems to disagree.