If Dubas doesn't balance this team we won't ever win. He had an opportunity to keep the cap in check and not overpay. To get some grit or rework the D and even keep a better tender. He sort of failed at everything.
A lot of Dubas' moves are frustrating: I personally don't care about drafting more specialized small skill guys like SDA, I don't really like Petan, I don't like Carcone, I think Ennis has been productive, but we probably could have a better mix of two way play lower on the depth chart, and I think it's silly to support Marner, Johnsson and Nylander with even smaller, less skilled guys. That's not how you bring a balanced roster to the playoffs.
That said, a GM's job in building a winner occurs over many years, not many months. This current Tampa Bay team started building in 2008. Steve Yzerman was brought in in 2011 and it's taken 8 years of his building to get to where Tampa is currently. Dubas has been on the job for 8 months. You don't solve everything in that short a run.