If user is uninstalling your application, it is reasonable to ask him what he did not liked in the application. Usually developers open web browser for submission of feedback.

IMHO this is not a good practise — most users do not like applications opening web browser without their confirmation. I consider it is a lot better to implement sending of such kind of feedback using desktop's regular mail application, such as Outlook and Thunderbird.

For example, this is IndieVolume Uninstall Feedback window:

Current version of InnoSetup, I have used in IndieVolume, was not supporting system font as well. So here is .iss pascal code to fix this:

Now, once all forms in Delphi application are modified to support Large Fonts and System Font ok, there are two forms outside of control. These are the forms that are invoked by InputQuery and MessageDlg VCL functions.
Fortunately, MessageDlg supports Large Fonts and System Font ok. InputQuery supports only Large Fonts, and does not support System Font.

Screenshot: Original InputQuery when System Font is Tahoma