William Shatner used the notion in one of his Trek novels (I forget which one, the second or third I think). Spock connects with the Borg and realises its not the first time (the first time being V'ger). The differences are explained by there being different sects of Borg, each doing the assimilation thing in slightly different ways. In the case of V'ger's sect, they assimilate via information and energy patterns.
So; an explanation, but I agree that it's a stretch.