You are right, this IS frustrating. I have opened a problem report for it.
As a workaround, you can follow these steps. I admit, these are only a little easier than editing the struts-config.xml. 🙂
1. After you modify the New JSP Path field of the JSP tab of the first page of the editor select Next instead of Finish.
2. In the Input Source field of the Form tab delete the “/form” from the front of the path.