Upgrade docs (#1182)

* remove table of contents

* remove more hard-coded table of contents

* remove comparisons, rewrite "why" section to be more general

* update intro

docs/Introduction.md

@@ -1,7 +1,7 @@
 
-# Introduction
+# Slate
 
-[Slate](http://slatejs.org) is a _completely_ customizable framework for building rich text editors. [GitHub ⬈](https://github.com/ianstormtaylor/slate)
+[Slate](http://slatejs.org) is a _completely_ customizable framework for building rich text editors.
 
 Slate lets you build rich, intuitive editors like those in [Medium](https://medium.com/), [Dropbox Paper](https://www.dropbox.com/paper) or [Canvas](https://usecanvas.com/)—which are becoming table stakes for applications on the web—without your codebase getting mired in complexity.
 
@@ -14,11 +14,30 @@ _**Slate is currently in beta**. It's useable now, but you might need to pull re
 
 ### Why?
 
+
 Why create Slate? Well... _(Beware: this section has a few of [my](https://github.com/ianstormtaylor) opinions!)_
 
-Before creating Slate, I tried a lot of the other rich text libraries out there. What I found was that while getting simple examples to work might be possible, once you start trying to build something like [Medium](https://medium.com/), [Dropbox Paper](https://www.dropbox.com/paper) or [Canvas](https://usecanvas.com/), you have to resort to very hacky things to get the user experience you want. And some experiences are just impossible. On the way, your codebase becomes harder and harder to maintain.
+Before creating Slate, I tried a lot of the other rich text libraries out there—[**Draft.js**](https://facebook.github.io/draft-js/), [**Prosemirror**](http://prosemirror.net/), [**Quill**](http://quilljs.com/), etc. What I found was that while getting simple examples to work was easy enough, once you started trying to build something like [Medium](https://medium.com/), [Dropbox Paper](https://www.dropbox.com/paper) or [Google Docs](https://www.google.com/docs/about/), you ran into deeper issues, like...
 
-Of course those are my own opinions, and if those libraries solve your needs, use them! But if you've tried using any of those libraries you might have run into similar problems. If so, you might like Slate. Which brings me to how Slate solves all of that...
+- **The editor's "schema" was hardcoded and hard to customize.** Things like bold and italic were supported out of the box, but what about comments, or embeds, or even more domain-specific needs?
+
+- **Transforming the documents programmatically was very convoluted.** Writing as a user may have been nice, but performing programmatic changes, which is critical for building advanced behaviors, was needlessly complex.
+
+- **Serializing to HTML, Markdown, etc. seemed like an afterthought.** Simple things like transforming a document to HTML or Markdown involved writing lots of boilerplate code, for what seemed like very common use cases.
+
+- **Relearning a new view layer seemed inefficient and limiting.** Editors were re-implementing view layers instead of using existing technologies like React, which forced you to learn a whole new system with it's own restrictions and gotchas.
+
+- **Collaborative editing wasn't designed for in advance.** Often the editor's internal representation of data made it impossible to use to for a realtime, collaborative editing use case without basically rewriting the editor.
+
+- **The repostories were monolithic, not small and reusable.** The code bases for many of the editors often didn't expose the internal tooling that could have been re-used by developers, leading to having to reinvent the wheel.
+
+- **Building complex, nested documents was impossible.** Many editors were designed around simplistic "flat" documents, making things like tables, embeds and captions difficult to reason about and sometimes impossible.
+
+Of course not every editor exhibits all of these issues, but if you've tried using another editor you might have run into similar problems. To get around the limitations of their API's and achieve the user experience you're after, you have to resort to very hacky things. And some experiences are just plain impossible to achieve. 
+
+If that sounds familiar, you might like Slate. 
+
+Which brings me to how Slate solves all of that...
 
 
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