Yes I agree..also because if the Romans could did the peace with the Parthians, at least they had a king with talk about, but with the Germans that situtation was very difficult because they were divided in a lots tribes. A questions: the Germanic tribes, how many warriors had?? Because they were always fought with Romans..
To be honest I don't know. I think that each tribe would have at least 500 warriors, probably more, and there were hundreds and hundreds of tribes. But when they grouped together they used to number in the hundreds of thousands.