The Borg were constantly being changed throughout their TNG appearances anyway. In Q Who, there was no talk of assimilation, the Borg only wanted technology, period. They had no interest in people at all, indeed it was implied the Borg are actually bred and grown on the ships, the Borg nursery was originally intended to be infant Borg, not babies who were assimilated.
Indeed, even introducing the concept of assimilation in TBOBW, Part 1 treated the very concept of turning Picard into a Borg as a unique thing that has only been done this once. It was Part 2 which suddenly and abruptly talks about assimilation being SOP for the Borg which it then became in all the Borg's subsequent appearances in the franchise. Really, the Queen is just the result of the continuing evolution of the Borg, which started when they were brought back in TBOBW.
Mind you, given the Borg were originally intended to be insects before the budget prevented that from happening, one could argue the Queen is more in line with the original concept than what we got in Q Who anyway.