Poland could be like the GRM in CtA, quantity over quality.

Since Poland was essentially knocked out so early in the war, they had little time to develop their army like the other allies. Therefore, there are two main ways to implement Poland into the mod:

1. The historically accurate way: Although Poland had no real army during the majority of WWII, many of their soldiers fought for the French and then the British using allied equipment. Therefore, their tanks would mainly consist of a mix of Renaults, Shermans, Cromwells, T-34s, T48 tank destroyers, etc. The only truly Polish tank was the 7TP, a very light tank by MOW standards.

2. Mixing Polish prototypes and designs with the allied tanks: Before the Polish army was defeated, they already had designs in place for medium and heavy tanks, however they never got the chance to build them. Examples are the 4TP (20mm infantry killer), 9TP, 10TP, and 14TP medium tanks, and the 20/25TP medium/heavy tank.

Polish contribution to World War
Her army managed to remain in the field through all five years of bloody fighting. Polish soldiers fought in nearly every major campaign in the European theatre.
Significant Resistance

VERY INTERESTING READING imo

https://en.wikipedia.org/wiki/Polish_contribution_to_World_War_II

Consider Special unit : 18th Pomeranian Uhlans 1939
https://en.wikipedia.org/wiki/Charge_at_Krojanty

Instead, the cavalry units were equipped with modern armament, including 75 mm guns, tankettes, 37mm AT guns, 40mm AA guns, anti-tank rifles and other pieces of modern weaponry.

1st squadron, to execute a cavalry charge at 1900 hours, leading two squadrons, about 250 strong. Most of the two other squadrons, and their TKS/TK-3 tankettes, were held back in reserve.
The charge was successful: the German infantry unit was dispersed.
... including cavalry forces, were formed by the Soviets. One of these units carried out the last Polish cavalry charge at the Battle of Schoenfeld, where a surprise cavalry assault succeeded in overrunning the German defensive positions.

https://en.wikipedia.org/wiki/Polish_cavalry#Cavalry_charges_and_propaganda

....Other cavalry charges of 1939 were as follows:
- September 1 - Battle of Mokra - 19th Volhynian Uhlan Regiment took by surprise the elements of German 4th Panzer Division, which retreated in panic.[5][8] During the charge, lances were used. In fact, the cavalry charge in the traditional sense was neither planned, nor executed. The mounted infantry rode over behind the attacking German armor in behind the tankettes with the tank men throwing smoke grenades to cover the approach
- September 15 - Brochów - elements of the 17th Greater Poland Uhlan Regiment charged towards the German positions to frighten[4] the enemy infantry. Shortly before reaching the range of enemy weapons, they dismounted and continued their assault on foot; the attack was successful.
- September 26 - Morańce - 27th Uhlan Regiment twice charged an entrenched German infantry battalion in the village of Morańce. Both charges were repelled with heavy casualties (the Poles lost 20 KIA and about 50 wounded, German losses are unknown). After the second charge the Germans sent out a soldier with a white flag and, after a short discussion with the Polish commander of the Nowogródek Cavalry Brigade, the Germans withdrew.[4]
...etc
Contrary to German propaganda, Polish cavalry brigades never charged tanks with their sabres or lances as they were equipped with anti-tank weapons such as 37 mm Bofors wz.36 (exported to UK as Ordnance Q.F. 37 mm Mk I) antitank guns, that could penetrate 26 mm of armour at 600 m at 30 degrees. The cavalry brigades were in the process of being reorganized into motorized brigades. The Poles also had the anti-tank rifle model 1935 (karabin przeciwpancerny wz. 35). Its calibre was 7.92 mm and it could penetrate 15 mm of armour at 300 m at 30 degrees. In 1939, the Germans were mainly equipped with the small Panzer I and Panzer II models, which were vulnerable to such weapons.

...
Polish ground troops were present in the North Africa Campaign (siege of Tobruk); the Italian campaign (including the capture of the monastery hill at the Battle of Monte Cassino); and in battles following the invasion of France (the battle of the Falaise pocket; an airborne brigade parachute drop during Operation Market Garden and one division in the Western Allied invasion of Germany). Polish forces in the east, fighting alongside the Red army and under Soviet command, took part in the Soviet offensives across Belarus and Ukraine into Poland, across the Vistula and towards the Oder and then into Berlin.
Formations:
1st Independent Parachute Brigade (Poland)
First Polish Army (1944–45)
10th Armoured Cavalry Brigade (Poland)
10th Infantry Regiment (Poland)
10th Lithuanian Uhlan Regiment.
10th Motorized Cavalry Brigade (Poland)
11th Infantry Regiment (Poland)
11th Legions Uhlan Regiment.

Strategy game is about units and how you use it to win.Poland wasn't WW2 combatant (knocked out in matters of weeks) so they don't have units for good play.Making another Nation that is composed 80% from other nation units and vehicles seems pointles.Better 10 really ballanced game nations then 20 unbalanced super-unrealistic nations.Whit this logic you could add Greece,Bulgaria,Slovakia,Brazil,Yugoslavia (with partisans),Manguko,♥♥♥. ally Siam,but it is pointles cause they nations in reality didn't had advanced mid-late game units to be competitive and trying to force push them in game is countproductive.As I said in start,RTS are about factions and they units and this nation don't have enough of them to be competitive.At end there is a GOOD reason DMS put Japan in game and not Romania.But,yes,you can give one faction a Tiger , t34 and Sherman and call that Nation X playable.But does this game really need another faction like that?Don't know about you but I think not.
P.S sorry for rant or bad English!

Yep, at this stage there is no plans for any other nation. I will deifinately not add al those small nations. There is some really cool balance and gameplay that can be done that is not in the default game. SUch as france and china have interesting gameplay imo.

"Making another Nation that is composed 80% from other nation units and vehicles seems pointles." I agree but it hardly justifies the existance of nearly all newly added fractions.

Poland cannot be underestimated as it was the largest allied military force after USA, UK and Russia. It is not like Finland took part in the operation Market Garden or were taking Tobruk or Monte Casino.

The problem is that Poland's forces were split to Eastern and Western front so for gameplay reasons it doesn't really help mixing Soviet and Allied weaponry and because it has already been done with some nations, there is no point of doing it again.

The other problem is that Strat is running out of ideas how to make minor nations viable and unigue in terms of gameplay.

I really dislike hearing people say to not add nations becasue they used someone else's vehicles.
There is infantry and also specials!