I like to think of it as a progression, even in apprentice mode Mage Wars has a fairly steep learning curve. There are still a lot of conditions, actions, spells, different types of spells, order of casting, revealing enchantments, etc. A full game of Mage Wars is more of apprentice mode + added depth and difficulty. Domination is a twist on the full game of Mage Wars that shakes up the general premise of enter the arena kill the mage, to one with different shapes and terrain and the possibility of winning with out having to engage only the opponent mage.
On the other side of the spectrum is Academy, familiar to players of other card games yet introduces some of the staples of MW like spell books, the type of spells, enchantments, equipment, etc. I enjoyed academy, but would not want a steady diet of just that game, but it facilitates two things. First is portability, If Academy was released at Origins I could imagine many people dueling in the open gaming area because all I need is table space, my spell book, and some dice. The second and in my humble opinion it provides a great introduction to the full MW game.
What is particularly thematic is the progression of the spells and mages.
Academy mages are young and use mostly level one spells, their spell books contain about 40 spell book points, and they duel in a small one room training hall. Apprentice mages are fully grown, have a wider variety of spells, books contain about 60 spell points, and duel in a larger venue. Full mages have all the items of the full game and 120 spell points. Domination is a battle in a unusual arena with a native population of terrain, conjurations and terrain.
Bottom Line: There is room for all three, Mage Wars will gain players, those playing academy may or may not move on but they are still playing mage wars. Just as Mage Wars Arena players may or may not play domination. It expanse the player base and, I believe, will lead to a healthier meta for all.