From a customer perspective, having bought a few themes recently, the search function needs more filterable options: colour, options etc. I’ve spent a lot of time looking for dark themes and had to go through every one!
If you go to say template monster (which isn’t as good – themewise) it gives you lots of filterab;e options.
Also i’ve purchased some themes thare are the same price but worlds apart in the functionality! WP titans have some great layout options (layout builder) and really allow you to change things up – this is an excellent idea and very flexible. Other templates are rigid and need a lot of csutomisation.