I've only read the first few pages, but I have to agree. The usage of white and the actual logo is great - it'll stand out on a shelf and attract attention - but the artwork itself looks pretty bad.
I could quite probably whip that up with 10 minutes of work, by simply taking a screenshot of the map and then slapping some character model cutouts down, plus some fancy brush effects. It's a really unimpressive cover on a technical design level, as well as a visual level.
One of the main problems is that there's no real draw on the "image" part of the cover. I hate to be a sheep, but using Julia would work really well - she is attractive as far as game characters go, and it'd also give the eye something simple to draw to. At the moment there's too much complexity and detail, meaning that the white stands out far more than the actual picture at any considerable distance. That isn't a good thing.
The one that the guy above me just reposted is a brilliant example. There's not too much complexity at all on the main image, so it's easy for the eye to be drawn to, but there's enough detail with the colouring and shadows for it to be very visually impressive and interesting.
I'm sure that the decision has already been made though, and no amount of amateur or professional advice will change anything. Trust me though, you could do far better than this - why you swerved away from the above design is beyond me.