Personally I think that as most of the popular manufacturers have an ACW range in their current catalogues do we need another one - albeit John's unique style and skill is an exciting prospect, like his entry in to the Peninsula War.
ACW like Zulus, Napoleonics and WW2 wil always sell well and ride high in the popularity stakes but I'd rather see a range of late 19th century European conflicts such as the Crimea, Franco-Prussian, Italian Wars of Independence, Austro Prussian wars that have been neglected by the likes of K&C, Britains etc
One particular conflict that I have always felt suited the JJD style would be the Boxer Rebellion.