Have One Interface/Window
Instead of having different windows for each task - scanning, viewing etc, just use one window for everything.
Scanning. It would be nice to just press scan and it put the file into the thumbnail view automatically - maybe have an option to configure the scan settings and it remember the scan settings that were previously used.
To me this suggestion is more of a personal preference thing. Lately even Microsoft, with its office suite, has started using separate windows for separate documents. In one sense having separate windows is an advantage because you can open and compare different documents side by side. Although the Quick scan idea is valid and I will create a new suggestion for that.