Since the ancient times Travian used to have 2 separate buildings to upgrade the Attack and Defense Stats of the units. This meant that Offensive players would build the Blacksmith and Defensive players the Armory. Besides this difference there was a significant change resulting from this split. Offensive troops were actually easier to kill. Some might argue that Travian Kingdoms favors a defensive play-style instead of an offensive one and this might sound counter-intuitive at first because you are "hurting" the offenders at first glance. But you are allowing for Ghost Armies to actually be a threat again. On top of the Defensive Bonus that the Smithy currently gives to Offensive units, you might have to face a Lvl 20 Wall and Lvl 20 Water Ditch. So this opens a long closed door for a different style of Offensive play that has been almost forgotten.
I would like to add some images to this thread to further back up my point but my noobness doesn't allow me to post images.