After just finishing reading my copy of BLB2 (great read). There are two situations that I think would really justify a special Warfare set.
Firstly the cannon misfire, is a perfect opportunity to finally see a model of a destroyed gun & crew. That can either be used a misfire stand or added to a normal stand to produce that overun position.
The second is the captured colours, I think there is a real need for foot/mounted ensign to be more active defending the colours.
For example you could have a mounted figure, striking down with his sword or discharging a pistol point blank?
Do you think there is a market for these additional packs?
Nick