Swords are a treat for the eye but unfortunately, they suck (on paper). The reason why is that they wound on 4+. Sure they hit on 3+, but if you go the hammer way, and fight a unit with 5 or more wounds per model, then you hit on 3 and wound on 3, which is better than hitting on 2 and wounding on 4 if you were to fight the same unit with swords.
If you've got yourself a buff, like azyros's, then you can hit on 2+ and wound on 3+ with your hammers.