The fact of the matter is that this just isn't a very deep roster. You don't need superstars across the board but the Bucks a couple years ago were known for very strong bench play and whether it be just the fact that they've gotten too old or just bad roster assembly, they just don't have to depth to adequately cover a major injury.
Acquiring Ibaka for DDV, any way you slice it, is a pretty damning stain on Horst's record. We get any adequate veteran for DDV instead of added dead weight and it would have helped a great deal in this series.