Has the AI really improved? Examples please?

[LeTharg]

I'm just a newbie. I played Version 1.19 with no mods and found the AI extremely easy even at high difficulty and high bonus. After going to the 1.27 with no mods, the AI seems better in the following ways that I have noticed:
1. Attacks seem to be with sufficient force to have a chance of winning. Several times AI forces approached a target, did not attack but rather waited for more force to move up and then attacked with sufficient force to win.
2. The AI developed faster and used research more effectively. For example, with 1.19 no AI ever detected my stealth ships. With 1.27, they surprised me by knocking out stealth ships fairly early in the game.

I don't have a lot of experience yet. I've only played one game: large galaxy, high difficulty, low bonus. At low bonus, the victory over the AI was still easy but I felt that at medium bonus I would have had a struggle.