Here is a work-around that I use but it needs a second monitor. Everything will be bigger and easier to read!
1. Open up the plugin and move to the second monitor.
2. Reduce the resolution of the second monitor until Superior Drummer/EZDrummer fills the screen or is a size that you like.
To reduce the resolution of the second monitor (Windows 7):
1. Show desktop
2. Right click anywhere on your desktop, choose - "Personalize"
3. choose "Display"
4. choose "Change display settings"
5. Click "Identify" - choose the monitor that you wish to have the plugin on, under Resolution: lower the resolution until you are happy with the results. Try to keep the ratio of width to height the same to avoid distortion (for example, change 1920 x 1080 to 1280 x 720).
Good luck and keep making music!
P.S. I agree, it would be nice to be able to resize the window