The loss of Papi's offense obviously hurt, but it's more than that. In theory (as people kept telling me before the season), we could make up that production at various positions, but we were counting on best-case scenarios virtually across the board to do so: the B's had to repeat what they did in 2016, Hanley had to keep mashing like he did in the second half, Sandoval had to at least not be a disaster, etc. -- and by and large, those things have not happened, or have happened only for brief spurts. Having a near-guaranteed 30 HR, .900 OPS masher in the middle of your lineup gives the supporting cast a fair amount of margin for error, but post-Ortiz, we no longer have that.
Dombrowki thinking he didn't need a middle-of-the-order bat looks a lot like Cherington thinking he didn't need a top-of-the-rotation starter in 2015: no matter how well it could be rationalized on paper, when the actual games got underway, the absence was glaring from day one.