The perfect font displaying program will:
Does any one program exist that does all of these? I would pay good money for a program like that.
You miss the sorting by meta-data. Apart from the other programs mentioned at the fontleech blog, I’d like to add another, which is not really a font program, but which does at least some/most of the jobs you want - and a great many others too.
It is the file manager program (shareware) Total Commander. In its own right, it is something everyone should have, as a replacement for Windows Explorer (that deplorable excuse for a file manager). One of the general functions is the ability to add comment fields to each separate file, which can be practical in some cases.
In addition to its general functionality, there are loads of plugins available, among them a font viewer which takes care of most of your other demands. At least 1, 2, 3, and 6 (it shows all available characters, not just the ansi ones or the windows set, like many other programmes). 4 is or is not taken care of, depending on how strict your demands are (there is no option - yet, but these plugins develop by the day, almost - where you can see the same line of text in 20 different fonts in the same window, but you can pick any number of files for viewing and either open them in separate windows, or switch between them much more rapidly and fluently than most spcialized font programs.
TC is not a replacement for a full-fledged font manager, but for the day-to-day functions, it is now my default application.