Troi has her empathic gift but like Boyce said: "Sometimes a man will tell his bartender things he'll never tell his doctor..."
To be honest, if I wanted someone to tell me about what might be going through a stranger's mind, I would want Troi on hand. But it wasn't Troi who got Riker to take command in the Best of Both Worlds, it was Guinan. Frankly maybe it was just the way Troi was used, but she never became the confidant like McCoy or Boyce. She was never the one who could go to her Captain and say "What's on your mind?"
Troi is a good person to help put the pieces back together. The others were good to help those around them help themselves before things got that bad.
Ever notice that many of the same people who want variety in life frown very hard on vanilla... But without Vanilla, Baskin Robbins just wouldn't BE 31 flavors.