I like the layout and design of the site, I feel that it can go far if maintained and promoted so long as you can get content creators to come and add value to your list of provided assets.

I tend to like making a huge variety of games and with that my asset needs vary (side-view, top-down, perspective, fantasy, sci-fi, generic and other) and the thing I have the hardest time with is finding prototype sprites for my player character(s) ie. fill-in sprites that will do until I discover what my game is about or what shape/size everything will be.

I recommend that you find/promote content creators that will fulfill these sorts of often overlooked kinds of assets. If you are able to do that you will not only have something for EVERYONE, but you'll also be a cut above what everyone else is doing.