Leaving out appraisal also would render the biological description of the phenomena of emotion vulnerable to the caricature that emotions without an appraisal phase are meaningless events. It would be more difficult to see how beautiful and amazingly intelligent emotions can be, and how powerfully they can solve problems for us.
Looking for Spinoza: Joy, Sorrow, and the Feeling Brain (ed. Houghton Mifflin Harcourt, 2003) - ISBN: 9780547541716