I talked to the API development manager and he said that this change affects most SolidWorks Corp add-ins as well, not just 3rd party add-ins. So the inconvenience isn't only for 3rd party developers.
This was a pretty high-up decision within SolidWorks Corp so you should tell this to the person in charge of the user interface. I forget his or her name.
A wrong decision by SolidWorks corp.