Show Custom Dialog should have the same simple-to-define fields for the entry of numeric values for position and size that we have with the New Window script step. It really annoys users when they cannot read the full contents of a Custom Dialog box.
There should also be an option similar to what we have for Adjust Window (resize to fit) so that the dialog would auto-expand or contract to display the text and entry fields.
Font size would be nice too. It would also be helpful if the entry field specified in a Custom Dialog could be set to use a date picker , checkbox, or radio button.
There are times when Show Custom Dialog is still preferable to popovers.