My opinion on goaltenders is that a lot of people are overly harsh on them.
It's the hardest position on the ice. A mistake often means a goal against, and when one is in a side that is poor, it only serves to make them look worse.
I think it's too early to give up on Bernier. He's shown glimpses of his potential imo. There's absolutely nothing to lose with him being here for the next 2/3 years and continue to see how he improves as the team and the protection he will receive does.
In any walk of like, not only hockey, people improve and reach their potential at different ages. In all sports the goaltenders/keepers usually develop later in their careers, as experience plays a huge part.
Taking one of Bernier's biggest weaknesses into account, which is his level of focus at early stages in periods. That's not a technical flaw that is irreparable in my opinion. That's a mental issue that can improve with time and experience.
He's 27, so in 3 years time when you'd like to think we might be looking at being a team that is pushing for the play-offs, he'll still only be 30. Therefore, in my opinion it's well worth sticking by him. If a fantastic opportunity to trade for a real exciting goaltender turns up in the meantime, fair enough. But I still believe he is talented, and that there's a consistent goaltender in there.