I can accept that Roddenberry ruled that mental health be just as important as physical health because that's a very real concern today, but if that's true, why does Deanna get a bridge post but not Crusher? If the answer is because Crusher has to deal with the well-being of 1,014 people, then the same is true for Troi as well (after all, the show established that she makes appointments, sets aside time for crew, and devises treatment -- just as a real therapist should). That's on top of research and studying she'd have to do for anticipated diplomatic missions as well.
The captain might be hogging Troi, when really the rest of the crew and future missions might be depending on her! Now *that's* dating it.
Reading this remark made something click with me, which is that, given the number of people on board the Enterprise, Troi should have been in charge of an entire staff of counselors. From
http://memory-alpha.org/wiki/Counselor:
By the mid-24th century, starship and starbase crews included a counselor, who was responsible for the mental well-being of the crew and civilian staff. The position was considered vital enough that it warranted inclusion in the senior staff of the Federation flagship; in that instance at least, the ship's counselor also had a diplomatic role, advising the captain in First Contact and other situations.
As with the chief medical officer, the ship's counselor has the power to relieve other officers and crewmembers of duty if he or she feels that their patient is suffering from a condition that may hinder their ability to perform their duties effectively.
This passage describes the role of a counselor, giving sufficient justification for one to be on the bridge, yet mentions no counseling staff. Dr. Crusher had a staff of doctors and nurses. Troi should have had at least several subordinate counselors under her direct command, which at the very least would have made her presence on the bridge less of an imposition on her time.
The fact that the burden of dealing with so much action was yet again placed on the shoulders of a single hero character, in this case Troi, rather than being spread among a responsible and capable staff of competent Starfleet officers assigned to the Enterprise, is actually something that I feel dates the show more, than merely her presence on the bridge.