The bigger and more importantly older Themeforest becomes, the more difficult it is to perform a meaningful search. I propose three solutions:
1) Ability to completely hide certain themes and developers.
There a few developers of big themes that hog all tags so that they come up in any search. Even more so when I sort by best sellers or best rated. Since I have not bought those themes in the last two years, I likely never will. But they push down other interesting and smaller themes and make them less competitive.
2) Filter to hide themes that have not been updated
What good is it for anyone to see themes that have not been updated since June 2014? I can only either filter by date added, but that does not show old and up to date themes. Or I can sort by newest but that only shows newcomers that I do not yet know if I want buy into.
I want to be able see to good old themes that are kept up to date.
3) Ability to filter by color
I know, this is difficult and possibly contentions, but it does make some sense. For example video themes tend to be dark and red, construction themes tend to be yellow or sometimes red, creative themes tend to have loads of white space and change with Apple-fashion, but they often have blue buttons.
So, if I am looking for theme and I know that I need a darker look, I search for video themes, even though I do need any video specific functionality. The same goes for yellow, I can search for construction themes but I may not want their macho look.
Now, you obviously say that I can CSS it all. Sure, but a) I may not want to and b) it may not work as easily, as you think it does.
I see as the strongest argument against it that it contravenes my 1st suggestion and that it would make the color search meaningless. There is a certain danger that big theme developers will again hog all colors - often quite rightly so because their theme come with dozens of pre-built color variations. But if my 1st suggestion were to be implemented this was not a problem.