Will you be putting more "meat" in this game before you launch an expansion, or will that be the source of any expansions?
I ask because the variety of monster and the number of spells are both a bit thin. One of the first things I did after my first game was to redo the spellbook, and after a few hours of work, I had almost double the spells, without touching particle forge. I can summon more than one of the minor things, without summoning an army, and that's just cutting and pasting(although "Summon Demon 1" does lack some pizazz).
In other words, it doesn't look like it'd be all that tough.
Also, let me ask this: Are you going to introduce anything to make the race choice more important? Wraiths should be more different than Men than their appearance, you know?
Finally, you have Ogres and Trolls as monsters, why not the other "normal" fantasy races? Elves, dwarves, and orcs have all been the most basic(from what I have seen) fantasy races used in fantastic settings. If you were to include them, there's nothing stopping you from including your own created races as well, you know?