definitely, terrain and fatigue have no apparent effect in RTW whereas these factors were very important in MTW... i am especially uneasy about the dumbed down effect of fatigue... in MTW, units came to crawl exhausted whereas in RTW they still run like gaselles...

in general, the MTW tactical AI was able to pull a trick or two and seemed more organized. nonetheless, i am not sure whether the decisive factor in MTW was not uber generals... i.e., try killing a Kata Prince charging into your troops... practically impossible without concentrated missile fire... in RTW, they still charge. however, in RTW they charge and die...

a whole different issue is the economic/strategy map AI... in MTW, it was hopeless... i used to explore AI faction's there using the "switch-a-faction-cheat". i could leave a healthy empire with several K in the treasury to the AI to control to find it deeply in red with unattended trade routes just a few turns later... hopeless, absolutely hopeless... :) haven't done such a test in RTW though...