Inspiration per se can of course lead to utterly original work in Type. Much Type design however, needs to relate closely to work that has come before, and this close resembalance can and has caused confusion and arguements. Especially for a Type designer starting out—it can be hard to understand where inspiration ends, and, to put it in inflamitory terms—stealing begins.
John Downer has made a serious attempt to distiguish between kinds or flavors of inspiration (or lack of it) in his article ‘Call It What It Is’. The article is often cited and has been influential. Maybe you will find it helpful as well. The text of the article has been put in the typowiki with the kind permision of John Downer & Emigre.
Call It What It Is