I'm pretty sure this has been tried before. You may wish to look over at
Project Gutenberg and see if that would help you out.
They started as a text-only storage of public domain books from around the world. It was required to submit books in text - as that was the format to last through the generations, as you argue. However, it quickly became apparent that they needed to allow some mark-up to identify some formatting; Italics, Bold, block indents, headers, to name a few. so they came up with their "tags" *Bold*, _Italic_ ===headers===, etc.
Then the argument said...why don't we allow HTML? A
clean HTML document is exactly the same thing but it could be read on many different computers: <b>Bold</b>. <i>Italic</i>, <h1>Headers</h1>
Then the eBook industry said...well, lets make a standard format that can be read by anyone and we will base it on very clean, very simple HTML....and ePub was born.
I honestly don't think creating a New/different markup style will help the industry - or readers for that matter - at all. I do wish you luck however. I have been known to write programs that do all sorts of things that no one else seems to appreciate as much as I do!
Cheers!