You have a short memory. There were many years the Blues were waiting to get a solid goalie answer. Legace, Mason, Halak, Miller, Elliot, Allen. UFAs, trades, home-grown...it was a long frustrating path before Binnington. (I could go back further and the list only gets sadder.) There were several post-seasons where the team was good enough to go a lot farther if they could have equal goalie play vs their opponent. Binnington broke that trend. Maybe he won't play to that level in the playoffs again, but he's at least proven he's capable of it. His 'mediocre' play the last couple years was plenty good to get the team into the post-season, so obviously it wasn't that bad. And last year he did it with no viable back-up as Husso was entirely unreliable.
I agree with the posts above talking about giving Husso a 3 year deal. Its no problem if he ends up winning the starting job, but paid as the back-up. I bet Edmonton would be happy to have Binnington this minute. He is movable if need be.