Still bunk. The hairy buggers were chiefly interested in making a profit out of the Romans - by trade, raiding, mercenary service, tribute payments or whatever - and for example were about the single biggest source of recruits for the assorted potentates' comitatus troops (the main Roman mobile field units of the Late Antiquity period, although as a rule initially founded to protect the relevant bigwig from his enemies...). Made good service too. Heck, entire barbarian tribes would migrate quite long ways to the vicinity of the Roman border in search of get-rich opportunities, with the obvious destabilizing effects for the border regions. It was even worse in the Dacia-Pannonia-Bulgaria region, where the only thing of any value the barbarians had to offer the Romans was manpower - be it slaves or mercenaries. Neither extensive slaving operations nor large bumbers of would-be mercenaries are somehting that add to the general stability or well-being of any area...