Ohh boi, I have to pick up a shovel and clear all this bullshit now, so lets go!
Initially, slot weapons had 0.25 accuracy modifier on them, 300% brought them up to 100%.
They got LMG and 0.25 accuracy was changed to 0.5 accuracy out of cover and 0.75 accuracy in cover, the LMG costs 75% of gren LMG, so overall DPS of the squad skyrocketed due to the change as
1) They no longer need to rely on radnom weapon drops as they have a reliable upgrade they can get on all of the squads.
2) Their DPS out of cover with slot weapons was increased by 100% of the old value, their DPS in cover was decreased by 25%, but point 1) makes it great BUFF thanks to reliability of upgrade, so no, its not a major nerf, addition of LMG and 100% DPS increase with it out of cover is a MAJOR BUFF.
Because they offered amazing map control in early game and it was impossible to drive them off the field with any mainline inf once 251 rolled out to support them, you would win all of the engagements due to attrition and staying power that combo offered to the point when they had to be nerfed to keep them in check.
You've mentioned nerfs, but completely disregarded why these nerfs occured.
This is first accuracy and cover modifier change:
This is 2nd:
Unless I'm somehow reading this wrong, its almost impossible for osttruppen to miss anything in cover with Kars and at worst case, they have little under 50% accuracy out of cover.
That's anything but low.
Their damage and therefore DPS is low, their accuracy is among the highest in game out of cover and guaranteed hit on anything in cover.
It is a lot of text that just blurs the picture. Osttruppen are really bad at everything apart from being diposable snare units and much needed in ost case recrew units. Apart from that their performance is just a joke and upgrading them with mgs is just a terrible idea to spend munitions (unless you are winning anyway).
The patch you are reffering to imo was a wrong approach. They should have increased their cost to make them less spammable but give them some more punch and better veterancy scaling.
Right now they can initially overwhelm a bit for a minute or two, but later they just become a problem as all the manpower you spent on them means you have fewer sensible infantry units on the field, and they will make you most likely lose the infantry war.
One way or another it is by far the worst in game mailine infantry, costing only slightly less than cons or grens. All the modifiers and stats you are quoting mean literally nothing here. Vippler is simply more correct - no matter how you twist it, they are just rubbish and useful only because of other 4 men ost squads unable to recrew stuff effectively (plus the fact that ost, for example, paks are crewed by only 4 men)