Does no one else see the problem with this much bloat? There are several.
1. Realism: These are battalions, and while that offers much more versatility and for more numerous unit types there are still limits. Flame tanks didn't fight as entire battalions, and I don't think any countries did or do field mortars in entire battalions which are better represented as organic infantry assets or simply as artillery.
2. Obvious superiority of certain units: When two units fill the same role odds are one is going to be clearly superior, it is a fact of life, perfect balance is impossible. This leads to the issue of certain units being effectively useless. Do ski mountain infantry fight as well as mountain infantry but better in the snow for only a tiny increase in IC? Then why ever use regular mountain infantry unless you are playing as Saudi Arabia? Do bicycle infantry have the same stats as cavalry for the most part with lower supply consumption rates (don't need to feed horses)? Then why ever use regular cavalry?
3. If everyone is elite than nobody is elite: Put simply commandos and "nation specific units" simply ruin immersion as it results in either A. never using them if they are inferior, or B. everyone is elite until I hit my cap at which point I have a hard number of elite units. It invalidates the idea of true special forces and elite units. Beyond that the SS weren't super soldiers and weren't better than the regular army, same thing with Soviet Guard Divisions and Rangers vs. other nations' light infantry. What made these units great was combat experience, equipment, and morale, all of which is better portrayed through unit settings (reinforcements and new equipment priority), sending them to the front all the time where the fighting is fiercest, and perhaps the ability to promote certain units to Guard or SS divisions, with an increase in supply consumption in exchange for a morale bonus.
4. Adds unnecessary complication to research and unit design. Lets ignore the fact that no nation ever made the distinction between light, medium, heavy, and super heavy TDs. So you have four paths to follow on your research tree. Which do you choose? Backtracking would be inefficient and a pain in the ass so you should either choose one extreme depending on how you foresee the future developing, or air on the side of caution and choosing the middle ground. Either way if you chose wrong (you choose light TDs because you imagine the war will be very mobile only to get bogged down where your mobility becomes useless, or you chose heavy and end up slowing your advance because of your slow TDs) you are out of luck unless you wanna backtrack your research and then completely reorganize your army to get rid of your slow TDs or unarmoured TDs. It could simply be better represented through a single TD line and using variants to decide the specifics of your equipment. Germany might slowly start fielding heavier TDs until they end up with the jagdtiger.
Honestly I would prefer a fairly simple route for unit types.
Infantry
Militia
Garrison
Infantry
Cavalry (bike or horse cavalry)
Motorized (ride in trucks or on motorcycles)
Mechanized
Light Infantry (mountain infantry and infantry specializing in rough terrain like jungles or dense forests)
Marines
Airborne
Armour
Light Armour
Medium Armour
Heavy Armour
Super Heavy Armour (eg. Lowe, Maus, E 100, TOG II, KV-4)
Tank Destroyers
Assault Guns
Super Heavy Assault Guns (eg. T28 and Tortoise)
Armoured Cars
Support
Artillery
Light Artillery (to support light infantry, marines, airborne infantry, or for the early war, cavalry)
Self Propelled Artillery
Rocket Artillery
Light Rocket Artillery (to support light infantry, marines, airborne infantry, or for the early war, cavalry)
Self Propelled Rocket Artillery
Anti-Air
Self Propelled Anti-Air
Anti-Tank
Light Anti-Tank (to support light infantry, marines, airborne infantry, or for the early war, cavalry)
Non-Combat
Engineers
Mechanized Engineers
Armoured Engineers