Considering how easy it is already to combine filters, arrange by values, and search values, I don't really think that's necessary. All you would have to do to find what you're looking for in that scenario is to select Sega Genesis from the side bar, then arrange by Genre, and then you can search for 2 player, and you'll easily be able to find the games that you want. It's not quite as easy as a custom search popup like that, but it's pretty close. I'll note the request, but honestly I don't think it will be a very popular request.