I'm not disputing that the strategy map AI could stand improvement.
But clearly you need to bump the difficulty and number of enemies up. No point on playing on medium against 1 guy when you've got more skills, right?
I haven't really noticed a big difference in the different levels of the strat map AI. A Medium strat AI seems to fight the same as a hard AI. And while Insane might be better I can't go there as I'm not that good at the RTS (hard is my max there). If the AI does change something maybe they should uncouple the strat/RTS AI so you could try insane strat AI/Medium RTS AI.