*Captain’s Log, Stardate 44824.4. Governor Leka and the representatives of the two moons are ready to transport on board. We have learned that they each have troops massed and are ready for combat if this final effort at peace is not successful.
Riker/Odan: Speak softly, Governor. Those who cannot hear an angry shout, may strain to hear a whisper.
The Trill host/symbiont relationship is far more centrally explored in the Deep Space Nine series, with a central character, Jadzia Dax (formerly Curzon Dax, later Ezri Dax) a source for many storylines.
Many of the characteristics associated with the Trill during the course of DS9 are absent here, particularly the spots along the edge of the face, which seem to consistently occur as a part of the hosting process. Further, the suggestion is made from the start that Benjamin Sisko, the central character on DS9, has known Curzon Dax for a long, long time, such that Curzon was Sisko's mentor. This fact seems at odds with the notion, expressed in this episode, that (as Deanna says) "We know so very little about them [the Trill]".
It's not utterly irreconcilable with the underlying basis for DS9, but it appears to require a clear retcon to explain it. This is especially true as the back story of DS9 identifies the beginning of the show as taking place only two years after the disaster at Wolf 359, and Sisko appears to be unconfused by the Trill host Dax shifting from the late Curzon to Jadzia, implying there and elsewhere he had known about that duality all along.