The goaltending was atrocious because they had a skeleton of a roster playing in front of them on a team with no true system in place for at least half the season.If they don't solve the goaltending issue in the next 3 months, there is no chance of significant improvement.
Like I said, a team like Buffalo this makes more sense for. They already improved and are at a phase where playoffs are the natural next step.
Goaltending will improve simply from having a healthy team in front of them. Let's not act like Columbus was a projected lottery team to start the season last year. By no means we're we expected to be solidified in a playoff spot, but the hockey world expected them to compete and then the wheels fell off the first month of play.
Staying healthy and adding Provorov and even a guy like Jiricek will improve the defense significantly.
And then on offense you add guys like Texier and Danforth back into the lineup, add a guy like Voronkov in the lineup (over a useless Roslovic and Sillinger) and it's not hard to see this team being miles better than last season.