I'm really hoping it does not turn into a dot// hack style plot, anime has been able to handle a lot of things but mmorpg's are not one of them.
the novel, from what i heard (since it hasn't been translated throughout) is pretty good, unless they botch the adaptation like bleach then i doubt it would be bad.
the story progress in this case is most similar to a mix of adventure RPG and a bit of militaristic plot.
if i'd relate it to some other series then it'd be close to maou yuusha with more emphasis to adventures.
or wait, i guess it would be much more closer to berserk if this is the case, specially the gore level if only they hadn't used CG.
while on the topic of mmorpg stories, from what i recall, those with action packed plots haven't gotten an animation yet.
to mention one, legendary moonlight sculptor (if ghibli were to take on that immortal legion arc it'd be beyond awesome, imagine mononoke with orcs and zombies instead of boars and humans).