MItch is a heck of a teammate. He's a really good dude and it's easy to root for him. He's also better than 99% of the people that play QB in the world. However, he's not better than the vast majority NFL starting QBs. I wish it would have worked out for him but it didn't. Where he was drafted was not his fault. I wish him all the best going forward.
Drafting QBs is a crapshoot. The year Cade McNown was drafted, there were 5 QBs taken in the first 12 picks (Tim Couch, Akili Smith, Donovan McNabb, Dante Culpepper and McNown). Three of the five were complete busts.
All the draft analysis I read had Trubisky as a top-10 draft pick. Pace obviously loved all the leadership traits that Mitch showed and probably felt they could fix any technical issues he had. They obviously got it wrong.
The larger problem is Pace has not drafted any other QBs anywhere in the draft. Tyler Bray is in his 3rd year as the 3rd string QB. He'll be 29 at the end of the season. He's not a developmental player.
When the Packers had Favre, they drafted Mark Brunnell, Matt Hasselback, Aaron Brooks and Aaron Rodgers. Brunnell and Hasselback were both traded. You have to invest in the position and, once you realize you've made a mistake, move on.
Peace