One thing that I feel would be a beneficial addition is the ability to select the races of the AI teams when creating a Solo League.
Currently, the AI teams seem to be random. If, for example, I create a 24-team league, I may want one team from every race. Instead, it will likely generate multiple teams from some races, and none from others. Conversely, I may not want to play against a certain race, but there is currently no sure-fire way to avoid a team of that race being assigned to the AI.
For an online league, when adding an AI team, you can specify the race of the team. I think it would be good if you were able to do the same for offline leagues.