Most MTW vets will say the exact opposite of this 2nd sentence is a better representation of how it plays. I still prefer the old interface (it worked better in battle.) The AI is so much weaker in RTW that it really pales next to MTW. There are many things that have potential and look great in RTW, like the strategic map. But the battlefield AI is one of the things pulling heavily into the negative category for RTW. A few things have been fixed in 1.3 but other things have been broken. The slow down made in movement speed for some units does help in 1.3 vs. 1.2/1.1/1.0.
The best indication of just how weak the RTW AI is: 1 vs. 1 match ups against identical opponents on the flat grassland map. You should win easily, even when trying to make it an even test.

With 1.3 1vs1 unit testing doesn't even work properly anymore.

The basic things the AI neglects, like its pila or warcry...or charging/running when it clearly should all weaken it considerably. Then at 40-50% casualties it tries to retreat 30 yards and gets slaughtered? WTF?
With ranged units the RTW AI is utterly hopeless. The MTW AI wasn't brilliant with them, but it wasn't brain dead, and at least could inflict some attrition.
MTW is more of a challenge on the battlefield, this carries over to the strategic map because army management is more challenging when you actually take some casaulties. MTW has more campaigns and distinct era's that actually have some meaning in decisive parts of the game.
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