She may not have been one of life's more charismatic personalities. And her wooden, stilted presentations, where she stuck doggedly to a rehearsed script, were awkward to say the least.
But her departure does raise some important points. First, it means the FTSE 100 has one fewer female executive directors, leaving just a handful such as Marjorie Scardino at Pearson and Kathleen O'Donovan at BTR-Siebe.
Secondly it begs the question why Sainsbury's persisted with such an odd board structure for so long.
When Ms Thorne was appointed to the Sainsbury's board seven years ago she reported to David Sainsbury who had just spent 17 years as finance director himself. She was always in his shadow as a result, performing the role of financial controller rather than the kind of powerful, lateral thinker that a company of Sainsbury's size ought to have.
Yet even when Dino Adriano took on the chief executive's job the post of finance director remained a downgraded function. Ms Thorne reported not direct to the chief executive but to David Bremner, the deputy chief executive. It was almost as if the company needed to have someone looking over her shoulder.
This set-up was odd to say the least. Nor did it help that Ms Thorne happened to preside over Sainsbury's finances at a difficult time.
But there is a wider point. It is an important function of a board, particularly of a major company, that it grooms its top managers for the top and ensures an orderly succession. In better managed companies, the finance director ought to be at least a contender for the top job just as David Reid was at Tesco. Rosemary Thorne, for all her qualities, was never that.
Sainsbury's has been criticised in the recent past for being a cosy family company that required an injection of new blood from outside. Yesterday's mini-shake-up illustrates that it is also struggling to develop talent from within.