Alright. I am almost certain I am a very first time visitor so I'll give you some feedback on what i like or dislike in my first impression.
The blue shade for admin is very hard to read against the drak gray background, granted, this varies from display to display, but from i can see there is not enough contrast between them. A test you can do in any kind of illustration to find if there is clear contrast is to change it to monochromatic.
Check what happened to the admin tag:

It disappeared.
Now, look at "Away Staff" I can actually read it clearer even though it is also a shade of blue.
This means you don't even need to change the blue completely. That being said, other colours might still work better.
It is great you have some options and including light skins. That being said, I would recommend to stick with a few that really work with your group roles colours.
As for strength, the Recent Activity that you got at the bottom was what got me interested enough to want to reply and it showed me better what is the vibe of the place. You could trial putting that module at the top to see if also get more of your visitors interested in checking the topics out and ultimately joining to participate?