This is one of the main reasons I havent played LTC for more than about 15 turns. It takes forever to move armies around. UAI mod increases the movement rates a lot and I am used to it... and I think it does help the AI. Since I have houserules where I never assault settlements, but rather wait for the siege to end, I dont think it makes it too easy for me.
But anyway, can I ask why you didnt increase movement rates in LTC? If there is a good reason that I dont know of, then I will probably play LTC. But it would be good to know if it would help the AI if I increased them.