I dislike Betazoid telepathy (I'm more of a Babylon 5 or Miranda Jones style telepathy fan). Deltan abilities are wonderfully nebulous and wider ranging
But perhaps only "nebulous" because we only saw the real Ilia in the first hour of a two-hour movie
. The general public had no idea about Roddenberry's novelization elaboration, nor Vonda McIntyre's ideas, nor can we guess how "Phase II" would have developed Ilia's abilities onscreen.
I don't think any
of the 13 "Phase II" scripts (and I've read about eight of them) bothered to develop her empathic abilities, nor did they explore the ramifications of her Oath of Celibacy and pheromones on Decker and others. We saw Troi doing Ilia's lines from "The Child" and "Devil's Due".
I think we learned lots about Betazoids - beyond Lwaxana - specifically in "Tin Man" (Tam Elbrun) and "Voyager" (Lon Suder).