The tower's soak was reduced; my suggestion is that it's increased above the brickwall's value.
With a higher soak than that, towers can function as an improved alternative to the brickwall - more like a fortress, or a castle keep. Not to mention it looks cool on screenshots. You could even make them cost more stamina to be built.
Towers are already very expensive and a brickwall gate would still be needed and therfore function as a weak spot on the perimeter, so I can't see how it would be unbalanced.