I´am not skilled with photoshop and programs like that, so I won´t be trying to win this contest, but while I was reading I had some ideas (some maps) that passed through my head.
I immediatly thought of a smaller portion of the map dedicated for the dragons of gold, of course with touns of yellow and gold around it; Something compared with the UK in the real world map.
Then in opposite sides, to represent the dark and astral we must have black and white, I would personally do very basic, and on the top side of the map, I would use white, and effects representing their cards. In the bottom of the map, with the same dimension, the dark with some cool colours (purple and gray).
Finally, but most importantly, one big piece of land combining the last 3 type of cards "red, blue, and green" (divided according to the creator/designer criteria), but with salient differences between the three elements...
If you read this until the end, hope you liked the idea, simple, but a good point to start making a dream come true, and as @aggroed said very easy to edit and personalise, along side with the development of the game.