Maybe you could write some comments about the creative process inspiring your themes and a "Your comments are welcome, they help me create themes." That might encourage folks to write about how they feel, but don't forget that there are "givers" and "takers".
I admire your themes and the courage it takes to publish them. I personally like darker themes, but that's only my personal taste. Yours are attractive and show increasing skill! Keep going! And satisfy yourself...that's the most important thing.
*P.S. Don't pay any attention to Zubaz.