Your post was very interesting and I learned much from it. I agree Bairgawulf, that relying soley on accounts given by Jordanes and other writers of particulary Gothic and Germanic history when trying to decipher with a degree of accuracy a point in history is rather dangerous, even though Jordanes' writing did rely on eyewitness accounts on some of his subjects as in the case of Priscus on Attila the Hun. Just like today in a world driven by political agenda and propaganda according to a writer's readership and sponsorship so too was it in the ancient world. Jordanes also wrote under sponsorship of Justinian and no doubt geared his writing to the popular opinions of the times. That is not to say he meant to be misleading and I have no doubt he felt himself objective on his subjects. Still, much can be learned from his accounts, as too can some credible history can be gleamed from regional mythology and folktales, such as the Elder and Poetic Eddas. However, I do agree it is important to read a variety of sources and look at clues from archaeology, philology and ethnography together rather than any single source. Provided other sources are available that is. On some things such as the death of Atilla the Hun there are widely varying accounts but no scientific evidence to use and we will never know the truth of Attila's demise to whether he was murdered or died of accute alcohol poisoning so we rely on writers like Jordanes to fill in the blanks as well as possible even if what they write should be taken with a grain of salt.
Sorry for rambling, I feel very strongly about the credibility of ancient manuscripts and accounts too. Back then I doubt if there were many "watchdog" organizations that would be standing by to take the writer to task should he deliver distorted sensational information for its appeal rather than its boring accurracy. : )