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