If your main area of experience is Sharepoint, then this is a good path to follow. I am seeing a strong demand for Sharepoint professionals, so you can choose to improve your knowledge on this area. If you feel that you can't move any further in the development
side, there is also strong demand for deployment and management of Sharepoint. There are both training courses and certification exams for either Sharepoint development or Sharepoint Administration, so both options are available to you.
Another area that you may consider is Business Inteligence. It connects nicely with Sharepoint; you can use SQL Server Reporting Services in Sharepoint Integrated mode, PowerView, Tabular models and PowerPivot, etc. So this track would integrate nicely with
your Sharepoint knowledge if you want to expand into something different.
