Thanks.
I did wonder initially whether Warlord Games would make one release for each of their rules systems. ECW would be a suitable release for their Pike & Shotte rules because they can fairly get away with a common sprue for both sides in the same way as the ACW package does and then add cavalry on later like they will be doing with ACW.
I think they'd minimally need to do a cavalry sprue for ECW, too, given the relative force mixes. They may be trying to bootstrap the epic line: first release one sprue; second two; third three.
They could probably get away with doing a basic Napoleonic set with 3 sprues. Certainly four. I think that's what they are building up to, but they want to see how this particular bird will fly.
For quick and dirty ACW, you only need rifled cannon, smoothbore cannon, infantry and artillery. Another plastic sprue with parrot rifles would be great. Cavalry or "clean" infantry with packs would be a could one for that.