I would say that the Crawford deal was the biggest unnecessary splash.
The thing the Sox did so poorly was to mortgage the future. The VMart and Gonzo deals both stripped the Sox of some premium prospects. And it forced them to fill holes externally rather than internally, and ultimately created financial inflexibility.
Signing Hamilton and Napoli may bump the payroll up, but at the same time, you've got guys like Middlebrooks, Lavarnway, Tazawa, Bogaerts, Bradley, Brentz, Webster, De La Rosa, and Barnes who are going to be coming up over the next few years and providing the team with impact players at league min salaries. That allows the team to go out and give Hamilton the 5/120, and give Napoli the 4/48, and still maintain flexibility.
This offseason, I don't really see any moves that would be made just to make a splash. I think, as depleted as this roster is right now, any move is going to be to build a winning team in the short term without putting any risk on the long term.