Will break up my thoughts under the main requirements.
Ease of navigation.
Plus and minuses to a CMS. When used there is the typical expected navigation so nothing special and not horribly interesting. The one thing I did like about it, which I am not sure I have seen before, was that when you visit one of your main categories it has those expandable/collapseable descriptions. That was interesting and seemed to work.
Found the "Player's Guide" after a few minutes of hunting for basically a What is Malvaria link and was pleasantly surprised. I didn't want to play though, just wanted to find out what the site was about s...maybe the link name could be more obvious for that. Once found though I found that while there were some awkwards sentences I think it is an excellent description of what the site does. And the site does do exactly what you described so the follow-through is good.
(very impressed when compared to my memory of your past sites!)
Ease of reading and overall presentation.
You probably expected this part. Eeeek. While I could get over the colors if I had to, the text on that wavy background is very disconcerting. It would be nice if the main links of the site were more easily readable. Wonder if you could make them bold just so they stand out a little better.
I remember seeing in one of the posts with the intentions of changing themes. VERY good idea. I can see the mismatch of the background inside the content vs. the outside of the overall content area. If you could somehow make all the areas with text have some kind of solid background color that would go a long way to making everything much more readable.
You already may know my unescapeable pet peeve about headings that eat up too much real estate. Your heading takes up about 1/3 of my screen but adds 0 to the site overall. Just forces me to scroll extra on every page load. Might be fixed with the theme upgrade though.
For all the main links, I think it would be a good thing if you had some sort of overview for each of the sections instead of just a list of links. Just to alleviate the click, list of links, click, list of links, a small introduction would break it up a little. The descriptions are usually pretty good, but it is all sort of plainly displayed and depends on the expandable links instead of jumping straight into something interesting.
Animals + Beastiary = Same thing, no? I see the difference but not sure if it is necessary. All the text is centered which makes for annoying reading. I would like a "View All" link or something if possible. I am not looking for specific animals, I want to view the entire list and just browse it and let something pop out at me. Hard to do with the links bouncing around the screen depending on what letter you are viewing. The alphabetical linking works, full list would just be very handy.
Game Staff App should probably be moved out of the compedium, same with Create a PC. The are more site management, not information on the world I think.
Might be handy to put a "Questions/Comments" (or similiar) link for those that aren't sure. Just have the link take them directly to the Newbie Forum where they can ask questions. There are always those that get there and wonder, "What do I do?" and don't want to read directions.
Content.
I was sort of expecting some kind of rules for players. There are rules for mods and volunteers but no explicit rules for players. It may not be needed in the games but having a major heading like that almost begs for a link for each type of user.
It looks like you have all the necessary information that a player may need to join a play. I was a little disappointed in the scarcity of the Geography section. This is where the world can really come alive yet all there was were a small paragraph on certain areas. What are "Salogeli" and the other red titles for instance? Viewing the forums may give some additional stuff but overall I would need more, unless the purpose was for the players to help define them. But then you would need another specific place for additions to the world to keep them all straight.
As I mentioned, I would definately enjoy a complete world description of the lands and countries. The war of Powers and Races is a good start for some history, but that without some kind of history on each city is only so helpful.
The magic is just there, a list of spells. What I want to know is HOW? How does magic work in the world. It can't be just "I am a mage, I can cast spells." What is the power behind it, why does it work, how is it balanced? Anything.
I liked the Races, thought those were really good, descriptive with plenty to make me happy.
Weapons and classes were ordinary, but necessary descriptions for a site hosting games. Organizations I am guessing come into play in the game since there was really nothing on them.
Journal? Are there any. I was wanting to check them out but don't want to create an account just to see them.
Overall, I am not getting the wow factor I need from it. It is a solid site and supports your PBP very well but, for what we are looking for as far as useable and original content, it just doesn't have the deep backgrounds and completeness that I think I need.
Great job though and keep us posted on your changes!