Were the Germans physically superior?

[Robert Vermaat]

Rome had into their army a lot of peoples from different parts of the empire, even germans, but again they DONT eat too much meat, their armours are small and the historiographic founts tend to exagerate their measures, germans were somatological taller and stronger even today, Slavic peoples are strong too, is genetic

Well, I would say, that's not entirely true, or maybe even totally.

Yes, sizes differed in the Roman army. Not only because (as you are right to point out) the Roman army had recruits from all over Europe, Africa and Asia. But also because size is NOT a genetic thing.

Yes, size can be something that a certain group is 'known for', but regional differences can be quite large, as can be the differences over time.
No, Germans are not 'stronger even today', that's nonsense.
No, Germans are not even 'taller today', that's the Dutch actually.
But even that is only because of influences due to environment and especially diet.

As much as Slavic peoples are not 'genetically strong', we cannot say anything about any group of people that lived 2 thousand years ago, simply by looking at their possible [!] decsendants today.