French. Why?

(1) The Italeri/Esci are in the wrong uniforms, so not in the running
(2) Airfix - enough said
(3) Zvezda have abandoned their set to match their Voltigeurs. This is your chance to complete one of your ranges - you have made the excellent Light Infantry sets, and we need French to go with them
(4) They fought every one
(5) They can be used for so many other Nations
(6) You mentioned head swap options - so they will be extremely versatile
(7) Your original French infantry sets (Bardin) are showing their age now
(8) The fat bodies 1808-12 set is difficult to mix with most other sets
(9) They may be usable with bicornes with your excellent 1805 French elites
(10) Because one can nbever have enough really good french, and they will supersede previous versions (not replace, as I have painted), but they will be a big order for me, and I imagine all the diorame builders will want them. The market is crying out for the definitive french 1/72 infantry set - so please match your MAC sets now.

let me know if you need any more reasons.

Others - Prussians, to match those excellent MAC format regular infantry

Austrians - because the other options are not well done at all. They are usable, but better sets would be welcome.

Russians. Unless you can beat the Zvezda set I will not be buying many. Sorry. I will buy some for variety, but not many.