This patch is split off from D2769 and a follow-up to D2760/rP24020 and D2986/rP24021. It gives rome siege wall towers four visible garrison slots (i.e. turret points), instead of the attack with up to two arrows other wall towers have. That rome siege wall towers are treated differently from those of normal city walls is justifiable, since they can be built in neutral and enemy territory and be used offensively.
How it looks in game:
[EDIT] Also gives all siege wall segments the same cost-to-health ratio.