Who is your primary audience? There is no point preaching to your choir. (Here your choir consists of you yourself, Emacs users and Lisp fans.)
I would argue that the site should be focused on persuading those who know little or nothing about Emacs to give it a try. Such a person is likely to be someone who has been weened on a combination of GUI and command-line tools. (My assumption is that anyone who does not already have some exposure to the command-line is a lost cause, but I would be happy to be corrected.)
Do not pitch as virtues aspects that a newbie most likely will perceive as a barrier to entry:
* Hence any mention of Lisp seems inappropriate. We had better hope that Emacs' Out-Of-Box impression is good enough to motivate - in time - an interest in Lisp, rather than presume it. Even more off-putting are the fine points of various Lisp dialects and Lisp extensions.
* Displaying Lisp code is probably not a great "come-on".
* The parenthetical "M-x list-packages" makes sense only to someone already familiar with Emacs.
Do not pitch as virtues packages that actually compare poorly to the competition:
* Notably Emacs' support for gdb pales before most IDEs.
* Newbies likely have a long, long road to travel before they will ever consider discarding their current GUI / WYSIWYG / web-based productivity tools for Emacs' text-only calendar, mail project planning packages.
Style:
* Generally brevity is a virtue. The text below the circular icons tends to be wordy. It feels like you are trying to persuade me by overwhelming me via "featuritis".
* Excessive use of 'including'.
* "Content-sensitive editing modes, including syntax coloring, for a variety of file types including plain text, source code, and HTML." (Awkward and - with two use of 'including' - hard to parse. What is a 'mode' to a newbie?)
* "Complete built-in documentation, including a tutorial for new users." (Those are two separate items.)
* "Full Unicode support for nearly all human languages and their scripts." (Language support is a bit of a stretch. The distinction between language and script is unnecessarily technical. I would mention support for editing of bi-directional text and support for additional encodings beyond Unicode (e.g. DOS code pages, ISO-8859-*, etc).)
* "Highly customizable, using Emacs Lisp code or a graphical interface." (A casual reader might take that as claiming we have a configuration GUI. Customize is really little more than a text-based forms package. It is better than nothing but I would avoid over-selling it.)
/john