I don't think we need more than 1 "Easy" Difficulty. Switch categories to something like that:
1. Easy
2. Normal
3. Hard
4. Ridiculous
5. Insane
6. Godlike
And yes add a lot of AI cheat to the highest levels. For example: AI should get a lot more heroes, half buildtime, research bonus.
Godlike should be goldlike! I don't want to win with a "1 Killer Stack" Strategy!!