Even if you don't mind abiding by the terms of the BSL, the licensing change is a signal that Hashicorp is in dire straits and doesn't know how to operate as a sustainable business. They're flailing about trying to increase revenue, and in so doing they're removing one of the core components (the open source licensing) that made their tools ubiquitous to begin with. And what will their next cash grab be?
Here's the kicker though... before the change to BSL, the future of Hashicorp didn't really matter as much, since somebody could fork their projects and keep them going. But with this licensing change, if Hashicorp shuts down one day, nobody could create a fork for several years.
So to me, whether or not I can use the software as currently licensed isn't the biggest issue. I want the ability to have an "escape hatch" should Hashicorp continue its downward trajectory or shut down completely.