Producers had a different science officer in mind for DS9
Before Jadzia Dax (Terry Farrell) took her place on the starbase called Deep Space Nine, the producers had a rather unique science officer in mind, one that had nothing to do with Trills. Remember that episode in the second season called “Melora?” Melora was an Elaysian whose species was incompatible with the strength of artificial gravity which was used mostly outside of her planet. This meant Melora had to use a special wheelchair to keep her grounded on DS9.
And that was exactly the type of character producers had in mind for their first science officer. So she would have been bound to a wheelchair in all of the common areas of the station but could fly around in her own quarters the way Melora did. The only problem with this idea was the expense. The cost of enabling the Elaysian to fly was too exorbitant for the effect to be able to be used more than a couple of times a season. So, for the most part, DS9 would have had a science fiction officer that was wheelchair-bound. Producers thought that defeated the purpose of having such a unique character.
DS9 could have used Melora for more episodes
Because the producers liked the idea of such a unique science officer so much, they brought the concept to life in “Melora,” and she was portrayed as feisty and determined to get by without any assistance. While critics weren’t particularly thrilled with this episode, had the character been brought back for further episodes, she could have grown more comfortable with who she was gradually. And she possibly would have grown on viewers (and critics).
Having someone with a bit more of an attitude (much like Ensign Ro had) could have added a little spark to the space station. A one-off episode simply didn’t give the character time to be fully fleshed out. “Melora” had a good premise, and the character offered an opportunity to bring another strong-willed woman on board the space station. While I wouldn’t have liked Melora in place of Jadzia Dax, I think seeing more of her character would have been a good thing.