Another reason why the "mirror universe" crap was even worse for DS9 than the usual BS claptrap retcon nonsense in TOS: In the "mirror universe" apparently the prophets and the wormhole didn't exist. But Sisko was specifically created by the prophets to suit their purposes. Without the prophets and the wormhole, there would be no Sisko. Maybe papa Sisko would have had another child, but it wouldn't have been with Sarah, and it wouldn't have been Benjamin Lafayette Sisko.