No, a craghammer is Superior. Goliaths don't get proficiency in it for free with that feat.Goliath Warden has Craghammer as a sub class of Hammer, isnt Craghammer like Hammer a military one hander ?
Any weapon-using character (defender or no) who spends a first-level feat on a superior weapon (especially if that weapon is a two-handed weapon, even moreso if that weapon is a brutal weapon) is going to seem super-powerful at level 1.