Totally understood. It's a worthwhile endeavor, I've been toying with the same kinds of concepts and have some of the same feelings haha.

I will say that if you're planning on storing keys server side you may run into resistance of people willing to use it. For some of the stuff I'm experimenting with, I've been testing out SteemConnect, which hopefully might provide an extra layer of safety into the process. I'm excited to see what Steemit Inc does with their 3rd party integrations too - should make our lives a bit easier! :)

I sent you a message on steemit.chat, not sure if you're a regular there or not? Either way - looking forward to seeing what you come up with!