Obviously some of the collapse was injuries and pen fatigure, but in the end of season presser Hoyer mentioned the uncharacteristic play of many players making defensive mistakes and lacking of hitting in high leverage/RISP, which they had excelled at during the summer push. The pen troubles are on Hoyer based on clear lack of depth, and its hard to blame defensive miscues on Ross for even Gold Glove caliber guys making bad plays. They probably were just trying too hard, but fatigue could also have been an issue which was on Ross.
When Ross had clear roles defined in the pen I thought his pen handling was fine. Some of his moves when the pen struggled, like continuing to rely on Fulmer after some blown saves, were odd, but I guess also somewhat
I thought his lineups were pretty good most of the time. The bunts were often weird though. He ran the running game well.
The Cubs seemed to have a well functioning coaching staff and positive dugout vibe. I dont think Ross deserved to get fired but it's hard not to think it's an upgrade. Maybe the Cubs thought he wasn't the ideal guy to break in the young position guys coming up in the years ahead, I really don't know, I didn't have a huge problem with his approach, but maybe they butt heads . We'll never know.