Baby had three pluses:
1. Positional and usage flexibility (PF or C, starter or bench)
2. Team defender
3. Dirty work defender
He has a lot of flaws - playing next to Dwight should actually help him, since Dwight is a human eraser on defensive mistakes I expect he'll maintain his defensive value, and have less usage on offense, plus get the weaker defenders.
But Bass is a much better player - a perfect backup for KG, and can shoot better and finish at the rim. He has all the banger skills that KG needs in the front court, and he's a natural PF who could shoot mid range or post up, when KG is on the bench. Plus the deal size and contract length.