It's a nice idea. I'd appreciate a tool that lets me enter a library and understand its merits along various dimensions. The problem with this tool is that it doesn't give me that understanding, as I have no idea what the grades mean.

The "enter Github repo, get information" part is there. Now you just have to improve the quality of that information. I think the tipping point past which you will suddenly get an influx of users is when someone can use your website as a tool to actually make informed decisions that they couldn't have without it.

Also, it's a tool for developers, so drop the Bootstrap! Either make it resemble the output of a Unix utility — sparse, clean, and compact — or go all the way and make it as gorgeous as Stripe's docs.