I think the patches do help with the inactive enemy armies. At least, AI expansion seems more dynamic in RTR Platinum (based on 1.5) than RTR Gold (based on 1.2); they also make more use of naval landings.

Kamikaze generals is not such a big problem to me - yes, the AI general usually charges in and dies, but - unlike say Shogun - it does not seem to be that decisive in battles (the AI is going to lose anyway) or in destroying factions (lots of replacement generals for a suicidal faction leader).

I'd strongly recommend a mod such as RTR Platinum that "fixes" a lot of the most commonly raised complaints about the gameplay (e.g. the uber cavalry you note) and historical accuracy of the game.