Huh, I don't remember that Crusher/candle ghost episode at all. Mayhaps I wiped it from my memory?
Lucky you, I think it was one of the later seasons, either 7 or 8. The series definitely started having more bad episodes towards the end (or at least forgettable).
Also had a rough start with some awful episodes (like the infamous Code of Honor), the series sort of started with the stories like those in TOS, but soon calmed down and came into its own - truly a TV classic.
After seeing Star Trek Discovery I'm saddened we'll likely never get a show similar to this again, it's just not flashy or action packed like producers seem to think audiences want these days.