Yes, this is true in part.
Part of my I give DW and now TMac some slack, is that keeping Thornton and Marleau as the core is something that 99% of good GMs would have done, especially after it looked like JT was turning a corner in 2011. Plus, both players give the Sharks a playoff spot...
With Tmac, he's generally regarded as a very good coach, the players have stuck by him strongly, and I have liked the general strategy he has brought to the team.
Lastly, I will say that if you fire DW for not hiring an effective coach or for bringing in the wrong types of core players, you also have to get rid of the coach and the players.
You do that before changing the players. I am sure boston's new GM would of rather had thornton on the ice when he took over with the new coach and front office. Then having to try and find a replacement, later on.