I think it is a mix. The biggest mistake made was signing Petersen before he was proven. He was essentially signed because of his World Championship performance and middling small sample size behind Quick. The contract Blake gave him was outright egregious considering it also included a NTC...
There are not many goaltenders like Quick. They are important, can steal games, and help propel the team farther in the playoffs, but I also think they are not required. I think you need a good goaltender; otherwise, you are just hoping for one to get hot at the right time, but it doesn't have to be a star goaltender. I honestly think Korpisalo is good enough, but I think there are many out there like him and because of our mistake with Petersen we will have to let him walk if they are hoping to sign Gavrikov which I do think is the more important signing.
Goaltending is just a position you can't screw up the money on. A solid $4-6M guy and decent backup are really all you need. They are going to let in bad goals, but they just need to keep you in it. This team is built around offense. They are hoping it becomes more balanced, but it isn't right now and honestly should have been run a little more like Edmonton where you just put all your stat points in offense and pray given the deficiencies this team has on defense, or they need to play a different system that is much more aggressive.
In the end, acquiring a goaltender shouldn't be as difficult as most obstacles in the way for the team, but it needs to be a precise move as there is no room for error. Copley/Petersen is not going to do it. Unless Petersen sells his soul to the devil and proves the hockey world and gods wrong, they are going to need to figure something out or buy him out and find a decent solution. If they can't find an obvious upgrade, like Hellebuyck, etc. Then I think they honestly should just bite the bullet, trade or sign Petersen, lock in Korpisalo, and run with it. The last place you really want to be is like Toronto or Edmonton and playing musical chairs for a goaltender will save your lives when you are putting all your chips in offense and ignoring your defensive line and coaching structure. Get someone in there that can do the job well enough and move on to upgrading the defense and developing young talent while looking to jettison TMac out an airlock sooner rather than later is my advice.