If RTW thinks the odds are heavily in his favor, he gets a hidden trait denoting that his battle difficulty was low. We use that hidden trait, along with another hidden trait denoting degree of success, to calculate a number of BattlePoints. The more BattlePoints, the greater the chance of getting a command star. The traits you see (Likes Easy Battles, Crushes his Enemies, etc) are just visible versions of these traits, acquired over time. The way I adjust them over time may not be accurate or may be bugged. Also, due to a bug in 1.2, there's a problem with a general fighting more than 1 battle a season.

If you want to help me figure out if there's a bug with this trait, start keeping detailed records like so:

Code:
271, Spring - Attacker - 1:1 Odds - Heroic Victory - Even Odds - Crushes His Enemies
271, Autumn - Attacker - 3:2 Odds - Narrow Defeat - Likes Easy Battles - Barely Victorious
This lists the year, season, whether you were attacker or defender, the battle odds on the scroll before the battle.

Hover your mouse on the bar between the two generals--In this picture, the odds are 3:1

Then tell me the outcome (heroic victory, close victory, etc)
Then tell me what traits your general had after the battle (Likes Easy Battles, Normally Victorious, etc) and if he got a command star from tactics or leadership or something else.

This would be a tremendous help in testing. As you can imagine, I haven't fought a lot of battles out over the course of a campaign myself, in testing.