Which total war game is better?

[Brandy Blue]

Which total war game has a better AI and gameplay? I bought Shogun 1&2 and Medieval 1&2 in a sale. For now I just played Medieval 1. I am not satisfy with the AI performance in managing their countries. I mostly fight against peasant while I am using Feudal Knight and Sergeant. Easy win in medium difficulty when the battle is auto-resolved. Needles to say that I am having difficultly to win the battle myself. Is the AI good on controlling battle? I think that is in my part who fail to control any battle well.

STW 1 has better AI than MTW 1 because it builds fewer bad units. However, in MTW 1 you can hand over management of your building and unit choices to the AI (I forget how) and then you have to use bad units just as often as your enemies do. I never played MTW 2 and STW 2.