for whatever content these are worth.. ;oO
.    http://web20-instruction.wikispaces.com/ELGG+strengths
.    http://web20-instruction.wikispaces.com/ELGG+Weaknesses
and some nosotalgia !;-P
.    http://www.tesl-ej.org/wordpress/issues/volume9/ej34/ej34m1/
looked hotz even back then ! hehh!;}

• lots of functionality out of the box
• experienced devs can change nearly anything via plugin, sometimes very easily
• PHP API pretty clean and documented
• great dev community with responsive core devs
• bundled plugins lack polish & include NO documentation
• almost no AJAX in bundled plugins, JS API is poorly/undocumented
• lots of undocumented conventions, views, etc.
• plugin order is an important setting and useful sites tend to have 50+ plugins
• requires experimental plugin to define ordered lists of entities
• no roles beyond "admin", and access system makes adding one difficult
• without roles, sites tend to have too many admins with too much power
• admin user mgmt tools are crude
• single "name" field for users
• bundled plugins don't allow transferring ownership of groups/objects
• built-in class autoloader is crap
• built-in notification system sends email in real-time: known to suck when groups/friend lists become large 

"plugin order is an important setting and useful sites tend to have 50+ plugins"

You can counter this with plugin_order, I just uploaded newest version here.

To be honest, none of the points you listed are critical for me (probably since I don't use Elgg out of the box). Performance was critical, although I found workaround.