Im from beta and i cannot remember your so called balance issue. The only light vehicles that existed was the m3 and nothing else because of the callin meta. you didn't use shreks to counter the m3 especially since the m3 was usually the rather common sniper+m3 combo and could nail your shrek squad with simple kiting.
i thought that the double shrek upgrade was added for easy use.
The fact that you don't remember it doesn't mean it didn't happen. If you don't know why pgrens were changed that way then don't say people who know are wrong.
There is no ease of use increase between buying one shreck when you have 60 muni, then another one when you have 60 muni again and waiting ages to get 120 muni, which was a fortune for ostheer back then. It was a straight nerf and it had its reasoning.
You also cant disagree with the fact that 3stgs + shreck is an absolute anti-everything doom machine and 2shrecks + 2stgs is unable to fight infantry at all. Especially as shrecks change models when they die, turning your AI off first.