Ironically, I was just reading an interview of Kawamori's that he gave around the time of the Macross Plus film came out in theaters. And part of the interview, he talked indirectly about his the no-reoccurrence thing. The guy generally feels a compulsion to constantly be creative and to try new things, to the degree that he dismisses entire mediums of artistic expression because they've been around so long that there's nothing truly new and novel left to do with them anymore. The entire point of coming back to do Plus and 7 was to make things that were radically different from each other and the Macross stuff that came before, and I imagine reusing characters and stories is a part of that mindset.