We base that on the relationships between the characters. Those of us that are big Voyager fans realized that the show was character driven and not particularly plot driven. Now there is nothing wrong with either way but if you tastes run to plot driven then chances are you don't care for Voyager as much as other shows. Conversely if you like character driven episodes then Voyager was good for you.
DS9 was actually plot driven with its big story arcs, some people loved that. Some of us love Voyager's characters. It's just different tastes.
While I understand where you are coming from I think that DS9 was as much a character show as it was a plot driven show. The fact is that a lot of the plot on DS9 stemmed from character decisions, such as Damar rebelling against the Dominion or Sisko lying to the Romulans in order to get them to join the war. I've just skimmed the episode list for DS9's final three seasons (which were the most "plot" based), and most of those episodes have a character based core. I am strongly of the opinion that DS9 was the most
character based Trek series.
But as always, to each their own.
This episode just laid it on a little too thickly in the first three acts for my taste. They go back to the big bang, the ship shrinks, they become a Christmas tree ornament, Riker shows up, Quinn saves Woodstock... it was all just too much. I'm also not a fan of Q showing up on Voyager in the first place; Q was Picard's nemesis, he shouldn't be showing up on Voyager just like I don't want Dukat showing up in the TNG movies. There was a time and a place for Q and it was called The Next Generation.
The bit where they visit a representation of the continuum was insightful and that rescues the episode somewhat. I can't imagine what it would be like to be immortal and to have done and seen everything I possibly could, and this episode brings up some good points about the pointlessness of being omnipotent. And how that feeds back into Q's realisation at the end of the episode that he was fighting for the wrong side is well done.
I'm a left-wing libertarian (if such a thing is possible) so I am strongly of the opinion that individuals have the right to do as they wish, especially choosing the time of their death. I just wish I didn't have to sit through three acts of sickly dessert before we got to the meat of the issue.