I'm often ammused how the word professional seems to be associated with wearing a uniform.
A uniform provides a rapid means of identifying certain people in certain situations for example the emergency services. It does not reflect their ability to do the job.
Thus a uniform is useful for prospective students to identify who are instructors.
This would not be required if more instructors were to show a bit more interest in strangers that walk through their flying club 'school' doors.
All that is needed is to be of smart appearance be it shirt, tie, club produced pullover. We don't have to be airline clones.
Be imaginative!