12/20/2020 CORRECTION: THE BETA VERSION IS READY, READ ON TO THE BOTTOM OF THE COMMENTS.
This mod is not ready yet. I've listed details of this mod elsewhere on the forum
viewtopic.php?f=331&t=53755but I can't post screenshots there, which is why I'm posting them here.
These are four examples of the changes in the forcepool mod. This is a work in progress and these might not be final examples.

- recruit comparison
- comparisonrecruit.jpg (242.71 KiB) Viewed 20045 times
The first is an example of the new units available in the recruit panel. The screenshot is divided into before and after sections. Top is the original, highlighting the large 9-element unit available in Virginia. I believe it was originally intended to have two regular and three conscripts, but the 1.06 database has it full of regulars. It is made up of five regular infantry elements, one zouave, one regular cav, one 6-pdr and one 12-pdr. The cost is enormous. The time to build is logical but excessive, especially considering this is the main way to get VA's manpower on the board.
The bottom half of this image represents the maximum size of a new VA infantry brigade, 4 elements: two regular and two conscript. The cost in money and conscripts compared to the vanilla brigade is about half, while war supply is about a quarter. It takes half as much time to build and doesn't require as much supply to maintain or ammo to fight. It can be used just like any other unit. The rest of the elements that would have made up a 9-element VA unit are available to build separately. You can see the zouaves off to the left, and there's also a single element conscript unit. In the screenshot I've got the filter set for infantry, but the cav and arty elements are also available to build. So all nine elements from the original unit are still there, but they're put together in a way that's more flexible for the player.

- beauregard comparison
- comparisonbullruncsabeauregard.jpg (313.1 KiB) Viewed 20045 times
The next image is Beauregard's Army of the Potomac at Manassas. In both examples Bonham is highlighted. The top half is vanilla. At this point divisions are not enabled and Bonham is combined with a unit that shares his name. The listed composition of the combination in the highlight is not particularly useful but it results from the way that individual leaders are combined with other non-leader individual units. Also note the line for seniority.
The bottom half is the new setup, and at this point a limited number of divisions are enabled for both sides. For practical purposes and to help some people wrap their mind around the concepts I am trying to introduce, think of divisions (or unit combinations) in CW2 as just combinations of two or more units that include at least one leader. A leader plus four brigades and some cavalry is a "division." A leader plus a single sharpshooter battalion is also a "division." My Bonham's "brigade" is actually a "division" in game terms, but the presentation to the user still contains "brigade" for some lip service to historical accuracy.
The composition of the combination listed in the highlight is more useful, in my opinion, but that's more of a function of the way divisions are listed than anything I've done. It took five units plus Bonham to build that brigade. Underneath, the infantry, cavalry and artillery are separate from each other. If you'll notice, the list of units and combinations in the stack panel are very similar to what it's like in vanilla. I have a couple of extra leaders that I included because they had achieved that rank by the time of Bull Run. I used historical battle order lists to build the combinations, which is why my Bonham's brigade is larger (and hopefully more accurate) than vanilla. The real life 30th VA Cav was divided up into companies and dispersed to some of the brigades. The game has converted all the companies into regiments. I scratched that and reduced the cavalry available.
One last thing I hope you'll note on this screenshot is that instead of "seniority", that value is called "leader position in current rank". Military seniority doesn't work like the game works, and "seniority" is a poor description for the game system. I think my description corresponds more accurately with the way the game works without adding confusion.

- johnston comparison
- comparisonbullruncsajohnston.jpg (273.36 KiB) Viewed 20045 times
Third screenshot is Johnston's command, and highlighted is Stonewall. The vanilla Stonewall brigade unit is five elite elements and costs four CP. Pictured in the stack panel are two artillery batteries with 20-pdr Parrotts, which were't present on the CSA side at Bull Run.
Bottom half is the new Stonewall brigade unit, and Jackson is set up much like he was at Bull Run, with the Rockbridge artillery attached. The new Stonewall brigade is only four elements, all regular, and costs three CP. I'll go into a long description of why I nerfed it if anyone is interested, but I give all the other elite brigades the same treatment. No unit (with the exception of ships) has more than four elements or costs more than 3 CP. The number of 3CP units is lower than the number of 2CP units. A lower number of 3CP units means fewer occasions when you have a unit costing 3CP but due to combat losses it's only down to one or two elements.

- union comparison
- comparisonbullrununion.jpg (340.02 KiB) Viewed 20045 times
The last screenshot is McDowell's army. The vanilla top half contains generals that weren't even there, or generals who were actually colonels. The brigade names for the units you're stuck with long after they've stopped making sense. I've highlighted Daniel Tyler, combined with "I/1st Bde". I'm pretty sure that unit de facto stops being the 1st brigade of the 1st division for everybody, including Athena, within seconds of it being unlocked on the board.
New bottom half has divisions enabled, of course, and the division composition should more closely match the historical battle orders I've been able to find. There is a large percentage of volunteers and conscripts. I'm considering knocking McDowell down to a rank 1, removing the army function so as to nerf his stack of divisions.
In my more perfect game world I wouldn't even be fighting Bull Run or locking the player into doing so. It would also include enlistment expirations for many of these early units. But those are separate, longer term projects and I'm trying to eat this elephant one bite at a time.