3. Ezri Dax
Dax’s story from Season 6 into Season 7 of Star Trek: Deep Space Nine is a sad one, both on-screen and behind-the-scenes. A silver lining to losing Jadzia, however, is that we got to meet Ezri Dax, as performed by Nicole de Boer.
What makes Ezri underrated is simply the fact that she doesn’t have a chance to come fully into her own. To be sure, de Boer gave an excellent performance, and the writers of that final season fleshed out the character in a number of episodes, but one season with a cast that size can never hope to explore Ezri Dax to the same extent that we came to know Terry Farrell’s Jadzia over six.
Even so, Ezri is a compelling character, and de Boer and the writers managed to make her distinct from Jadzia while still making it clear through actions and behaviors that the Dax symbiont lived on within her. In fact, this is arguably a valuable event to witness with a Trill character.
Through Jadzia, we had learned about the past hosts of the Dax symbiont through dialogue, flashbacks, and the Trill rite of zhian'tara. This certainly spawned plenty of interesting stories, but Ezri offered the audience a chance to experience what it's like to lose someone and have part of them return in a new host. It lets us better understand the experiences of characters like Worf or Sisko.
The issue is mostly just that, with one season, Ezri doesn’t get the chance to expand very far beyond being Jadzia’s successor. With what we do see in Season 7 of Deep Space Nine, however, shows that Ezri is a compelling character who deserves more, both from Star Trek and from the fans.