Add immediate help...
One other way the Blue Jackets could use their open cap space? Strike for immediate help within their lineup. While I don't think Don Waddell is going to do this in the short-term; once he gets a better grasp on things and after some evaluations, this is a possibility.
As it stands, the team may have one bottom-six job up for grabs. They could fill that from within (James Malatesta?); but for a team trying to turn the corner and start winning hockey games, that may not be a viable solution.
They could also look for a top-six forward upgrade, or - dare I say it? - a top pairing defense option to play alongsize Zach Werenski. With this much cap space, they could conceivably go out and acquire any player in the league, depending on who is available and what they're willing to give up.
It's entirely possible that the Blue Jackets go through the majority of this season without any major changes. But, having this kind of cap space available means that they can explore every option that comes their way.
At the very least, they should be able to have a successful trade deadline, whether selling, or (if we're dreaming) buying. It's a nice situation to be in, heading into the season. Having flexibility is never a bad thing.