I liked the challenge mode, but it was rather short. I guess the most obvious suggestion is therefore, whether you will make some tools to the community available which allows them to create their own.
And another suggestion:
You could also do the challenges, in which you present the player a certain game board and then ask him to find the way with the highest success rate to reach a goal (i think this would be a good training too)
Edit: I understand, that this is something for the distant future