Wonderful news, your expansion of the WSS-range and the new box cover!
Which sets are need still....
a generic bagage-/artillery train (wagons) which won´t been a problem for all armies because there were mostly civilians who were hired for the transport-wagons (oxes were still widely used for big loads)
a working/digging pionier-set with civlians and soldiers without coats and regular hats
a big mortar set for the many sieges of this war
All good ideas, but the idea of a baggage wagon/carts, with some horses and non-combatant drivers, camp followers etc would be a different and very useful set.