MMC has been manging expenses very well since Glaser arrived. He is pretty cold blooded about how expenses have been managed. A number of lay-offs, no raises for the people who get the majority of the daily work done. Lots of people retiring and many more who can't wait to retire. And many many people who are looking for a more active job market to look for other work.
The real question, in the next six months, is that there are a number of expenses that the management cannot control. As responsible mangers, they really want to accrue expenses as they occur and not try to delay recognition. For example, the MMC pension in underfunded by around 15-20% which is lots less than at AON. But they will probably make provisions for payments on the pension obligations, which will cut into the profit margins.
I think these shares are close to fully valued right now. I would personally rather have my money in an ETF like VPU than in MMC.