Although a corporation is soulless entity, the people working in an organization are not. I'm fairly certain that the corporations I've worked for technically had only shareholder value optimization as an objective, but that doesn't mean that the managers treated me unkindly. I was given leniency with partial days off, working from home and leisure time when things were slow. The managers wanted to make me happy because they wanted me to continue to work there. Also my job consisted of problem solving which required a creative element that cannot be extracted by force. The same is true for the corporations I do business with (e.g. fast food restaurants have to obligation to give me free water)

For that reason, I don't think there needs to be an explicit statement of maximizing stakeholder well being.

I'm not surprised that many managers and business owners like this idea, as it gives them more flexibility, but that's not necessarily a good thing. It allows them to finance pet projects, grow bureaucracy and overall be immune from business concerns.