a lot of german tanks got large kill counts, yes this is not something one can dispute much (apart from claiming exaggerated kill counts, but that is not the topic). These heavy tanks (ferdinand/Elefant, JT, KT) are all extremely strong tanks (armor and gun wise), this is undisputed, but the CRIPPLING reliability meant that these "unstoppable" machines were knocked out by themselves, their operational ability also impaired, yada yada bla bla. Their low production numbers meant that each loss was significantly more devastating than the three or four tanks it single handely killed. Their cost was also extreme, each of them costing several panther tanks at once.
Instead of making several more lighter tanks that were successful enough, one went above and beyond to make expensive heavy tanks that were probably overkill until the advent of the is-2
TLDR german late war heavies are overrated, "lighter" tanks were a better idea
most tanks were expected to last around 1000km but the german (heavy) ones in particular could (and did) break down or set themselves on fire pretty much immediately. Allied ones could break down well before the expected time, but these allied tanks were way easier to repair than overengineered german ones
but this is coh2, the only thing that matters is german mythology on armor and massive armor/gun size with formula 1 panthers
You are right on the "heavy vs light" debate as it happened historically.
Speer (the man that laid the groundwork for mass building anything in Nazi Germany) recounts in his memoirs how "heavy tank mania" crippled Hitler's ability to make sound combat decisions.
When they came across the T34, he vividly recounts (Inside the Third Reich
, Speer) how surprised Hitler was with not only the T34's main armament but also by the Zis anti-tank ditches. He almost immediately took over armor design from the Wehrmacht's Committee for War Production and ordered heavy front armor vehicles built.
Speer however, put some limits (due to the very crucial crude steel shortages Germany always experienced) on the tonnage of these new machines. Incidentally, the original contracts given for the "Tiger" machines put a strict limit of 40 metric tons for them which was considered very heavy at the time, hence the name "Tiger" for a very heavy hitting big cat.
Hitler personally overrode this, and asked for more front armor supposedly to tackle the threat of said ATG ditches. As such, the Tiger tank got its final combat weight of about 55 metric tons.
To once more offset this, Speer along with OKH asked for a more agile and nimble tank called Panther for taking on T34's built. Its original weight was to be no more than 25metric tons, and its original vision was a far smaller calibre gun alongside less armor attachments. Its main military usage would be to traverse long distances (owing to an almost perfect engine type being) whilst maintaining combat readiness at all times, something T34s could never do.
Once again, Hitler personally ordered the Panther to be considerably beefed up from the armor side and also the gun side whilst not allowing it to have a better engine. As a result, the final Panther had the tonnage of the original Tiger of about 44 tons.
Honestly a pretty captivating book. Well worth the read.