I made a little self-mod a while back that doubles movement points. If you can avoid using it to blitz behind enemy lines then most of the time it is very useful for many things, especially roleplay since my generals don't age 30 years coming back to the capital. A side effect is that AI empires tend to expand very aggressively. I have games that have only run a few years and pontus has a few cities and is preparing to take Byzantion and the Hayasdan have complete control of Armenia. Makes for fun times.

In the end I had to introduce negative modifiers for Ptolemy and AS though since the bonus makes them too powerful and able to throw their armies all over the place. But fun times.

And back o topic, yes I do notice a difference. The Ai tends to be less passive on higher difficulty levels to my mind. But I can't be too sure.