They were going to do something with Sito Jaxa on DS9, have her come back from the Cardassians, but the writers felt it would've robbed 'Lower Decks' from it's ending.
I liked Taurik, but I automatically like all the Vulcans that appeared on screen. Lavelle felt a lot like a younger Riker, but I have the feeling that was the point. Nurse Ogawa was developed enough, and I feel that 'Lower Decks' was mostly about Jaxa, Lavelle, and Taurik.
Ben's role was pointless. Completely and utterly pointless.