That's a potential hen and egg problem. Do the HD and HD+ rank higher, because cb put that in their algorithm or do they rank higher, because users prefer high quality streams?
I still think we're all thinking too cb-ish, because we all know that cb only has this one way of presenting rooms: one long list divided by pages and sections, which are again a long list divided by pages. But there would be more possibilities. Very simple one: just put more rooms on one page, make thumbnails smaller, make it all a scrollable list, make a new tab or section "recommended rooms". Give users more options to sort their list of followed girls. Think outside the box
I still think we're all thinking too cb-ish, because we all know that cb only has this one way of presenting rooms: one long list divided by pages and sections, which are again a long list divided by pages. But there would be more possibilities. Very simple one: just put more rooms on one page, make thumbnails smaller, make it all a scrollable list, make a new tab or section "recommended rooms". Give users more options to sort their list of followed girls. Think outside the box