Tactics Ogre was made before Final Fantasy Tactics, so it's a little less refined. I still haven't played either yet, but that's what I've heard.
The tactic used in battle doesn't really affect Alignment. Killing higher-leveled enemies is more lawful, while lower enemies is more chaotic.
In 64, the biggest overall factor is the initial Alignment of a character; characters' scores even out in their unit. So you can cause a character to drop it quickly by putting him in a unit full of Skeletons (Chaotic). Overall though, it's really easy to make Lawful units, while I have only a few Chaotic units and virtually no Neutrals by the end of the game.