The Dogs of War

Some consideration was given to having Quark become the Ferengi Grand Nagus in this episode. It was decided that his character represented a sense of continuity on the show, however, and he needed to end the series still owning his bar, as he had before the series began. Armin Shimerman greatly approved of this decision.

Quark's speech "the line has to be drawn here. This far and no further!" was a parody of Picard's use of that line regarding the Borg in First Contact - another example of Ron Moore taking great pleasure in mocking his own work.

Similarly, his line that "This establishment will be the last outpost of what made Ferenginar great!" harks back to TNG's "The Last Outpost", the very first episode to feature the Ferengi.

This episode marks the final appearance of the characters Rom, Leeta, Grand Nagus Zek, Ishka, Maihar'Du, and Brunt. It's also the last appearance of background characters Broik and M'Pella, who were allowed to have speaking lines for their last episode.

In Zek's last episode he announces his retirement and names Quark as his successor - which is what he did in his first appearance back in "The Nagus"! And in both cases, Quark ultimately doesn't get to be the Nagus.