[Sombre]

I don't think it makes sense. Elephants trample not only because they are large, but because they can't fight - they just stomp along crushing things. Minotaurs can fight, but are bullish enough to squish people under their hooves and so on.

Trample is used by units which use their bulk to simply crush enemies.

As for repel and trample, well I think repel should work vs trample by checking length against size. So pikes could stop elephants trample if they passed a repel test and the elephants would then use their trunk that turn. Spears could stop minotaurs (unless they were berserk) and force them to use their axes, but spears are length 4, too short to stop elephants trampling (size 6).