"The higher cost for different factions seems interesting though, how do you get that to work? I don't recall an option in the editor that can set different costs for different factions"
I'll play around with it and see if I can figure it out. I know it can be done, as the MA scenario that comes with Conquests uses it. If you'd like to see yourself, you could just run the editor on that scenario. I think what it does is make the entry techs untradable and expensive, then give them free to the appropriate faction. So Life mages would get Life I, VI, and XI free, while needing to research the corresponding Death, Nature, and Chaos techs themselves at a higher price.
I'm currently finishing up my first Master of Myrror game as Merlin (excellent UU, BTW), and there is a lot to like, especially for an old Master of Magic fan like me.
Strengths:
1. The whole Elves, Dwarves, etc.. system is outstanding. Lots of strategic depth and potential to do even more. Pls retain the rarity of these resources.
2. Good variety among factions across a wide range of variables, creating good replayability potential.
3. Actually interesting late game wonders, such as Bind the Sea, that are worth building.
Areas for improvement:
1. Tedious late game. You address this with the high-cost, high-HP later units, but this should be extended to racial units (up the HP's, tone down the spawning frequency) and artillery (up shield cost and rate of fire). Late game turns take forever to move the 200-300 units. Same phenomenon with the 6 turn research min. In my game, the AI is not researching the racial optionals, so I've had to sidetrack to pick up those to finish out a game I largely had won ten hours ago. Yes, I could have skipped them, but then victory might have taken even longer, as those high-level optional racial rally points are quite powerful. Also noticed the AI has trouble fully utilizing them.
2. Limited government options. Nice variety among the available governments, but no opportunities for strategic decision-making in current system.
3. Non-aligned techs are too easy to get. Life mages should have to sweat to work death magic, and vice versa. Suggested means for implementing this above.
All that said, very enjoyable mod - thanks for all the hard work.