Pat, hi. What I have observed from your themes lately, you changed your style in a dark way (in a right way I must add) after you start with K800. I know that dark themes is appearing very good on K800 but not on most computer monitors.
Its a pitty but the reality. So people looking at your previews can not see the details of your work. And your themes are not getting what they deserved, is my opinion.
So what I suggest and you should do is to make brighter previews especially for the forum. Yes, it will be some extra work but necessary for to discover the real beauty of your themes.
Just my opinion.
Btw, the last one is great and I am looking forward to see the whole theme.