For me, themes are mood objects. I decide that today I need a red one. Maybe because that fits perfectly to my outfit or my desktop theme. And then the scrolling starts.
If I could sort them, I had a category red, green, blue ... . Or one for the weather, holidays ... . Even if I just had the possibility to move them to different positions, then I could move all red ones together, followed by green ones ... .
I hope this is not too much of a big act and can be easily performed by the themes specialists. I would really appreciate.