Ogres has limited usefulness. Stealing movepoints isn't that bad, but in this bout, he loses to almost everyone. Besides, I never found it useful... Low Atk and Def, 50-60 damage and 680 HP for 1000 leadership. I'd take 4 paladins over 1 ogre any day.
Giants - once gain, limited usefulness. Atk and Def are generally decent, but he is very, very slow and that earthquake ability reduces its effectiveness with distance (100% for the enemies next to him and -10% per cell away).
This is why these 2 units aren't exactly popular
