I agree that desert tournament is a great map for training, perhaps more variety of maps would be welcome. Unfortunately, one thing that is really difficult to do with the AI is that you have to adapt your strategy to the map, and the AI can't really do that.
Desert tournament is great in that it balances early game with mid-late game, but it does llittle for a huge map with really late game big armies. I think ice wars would be a good map to temper the training with some adaptation for large maps.
It works like that in nature, but for our AI training it's bad.
the idea is that an inefficient training cycle that can be fully automathized and run authomatically a huge number of times is better than a more refinined process that requires human input and is slower. Inefficiencies caused by statistics tend to even out in the long run. It's the zerg rush equivalent of problem solving.
Did you find out that the starting positions of Desert Tournaments have big quality differences? For me it looks like they are very similar.
there are some small differences, one of the players have slightly more land and one slightly less. Not sure oon specifics, I remember during the 2015 tournament I was able to make one extra farm with a couple of starting places. Difference is minimal though, can be considered equal for all practical purposes. If you can train the AI to the point where that tiny difference actually matters, it's already a great success.