You seem to be limiting artist by only having it be digital. Some artist like doing both digital and traditional. And those artist may get discourage to join since they will only be allowed to post their digital and not all of their art they like to do with fantasy themes. And there are some artist that have artwork that is mixed with traditional and digital in on piece. Otherwise, it looks like a nice site. Glori305 is correct about the front page wording. You may want to change some of the wording so it sounds less like opinions and more of an art community intro.
Your site's front page has several we don't want "things like photography, writing, artisan crafts, fractals, 'fine art', etc, don't really fit" and "fetish art is not allowed! Fan art is discouraged"
But you are looking for " people who are already into drawing,and somewhat serious about developing their skills, but not necessarily up there with the masters "
Also, you have no examples of the level of art you are looking for. Already on their journey, and not yet a master, are very subjective terms, a quick look at your gallery, and there are going to be a lot of DA's population that looks at our work and gets discouraged that they will never be as good as a master like you.
BTW, you have fanart of Trek in your gallery....are you only going to discourage MLP fanart?
Most people who are just starting out do fanart, and even those who do not do so exclusively, sometimes do a piece from time to time.
I am automaticly excluded from your group, my drawings are only done for practive and to do rough sketches for my sculptures, but you have ruled out sculpture. You have ruled out a huge amount of DA by saying no fanart. And many of the non-fanart fantasy artists are of the kind of quality where they are selling their work, which makes them sound excluded as well. Which rule out someone starting with drawing/painting/digital and moving in to another medium. They decide to branch out into sculpture, their art is no longer welcome.
In short, you are looking for a very specific type of person. Considering that most of DA does not hit the forums, you are probably better off searching something like "dragon" or "wizard" finding artists in the appropriate levels and inviting them.
Might want to make the front page more inclusive, saying that "Orginal art and concepts are highly encouraged" is more inviting that "Fan art is discouraged" and calling anyone's art creepy, even if you feel that way about fetish art, is going to limit your audience. There might be someone that does both fantasy and bondage art, who's fantasy art fits in your groups theme, but you have just labeled them a creep. And while we are on the subject, saying shyness is acepted but fetish is creepy is going to turn quite a few people away. Judgementalism scares off shy people, that is usually why they are shy to begin with.
I can't imagine that category menu ever actually being used, as the site's not likely to get big enough to need it; instead, you can see essentially everything important that's going on on the site by clicking the 'Community' thing, which shows all recent art, thoughts, comments, etc. I've designed sites before with a similar format, and it seems that most people don't use any other page than the Community one, once they've got used to it.