After watching this show many times, I have asked myself what purpose should a Betazoid psychiatrist have on a starship. In regards to Deanna, I believe that a psychiatrist had no business on the bridge of a starship. She was not qualified to be in a position to outrank officers like Data in a crisis situation.
She originally had the rank of Lt. Commander and later on in the show, she decided to take the proper tests to gain her Commander/Bridge Officer Command qualifications. There were other officers in many other areas of the ship, such as science officers, engineers, medical officers, whom all had Lt. Commander or higher ranks..... but just because they have the rank, doesn't mean they are qualified in taking command of the ship.
However in the episode "Disaster" by default, she was the higher ranked officer, thus, by protocol, she would have to assume command, which she did.
In regards to a psychiatrist not allowed on the bridge, I disagree because I am pretty sure Picard wanted her there... and if the captain of the starship wants someone on his or her bridge because he or she thinks they can benefit or otherwise have an advantage in a situation, then who are any of us to argue?
When she did eventually pass her command exams and such, she officially had every right to be on the bridge and very well could take over command during an emergency.
It felt rather Soviet-like with a political officer sensing the Captain's thoughts to make sure they were 'correct'.
She wasn't there to tell people what they should or shouldn't do based on her own opinion of the matter, she didn't have such authority. Also, she couldn't sense anybody's thoughts.... only their emotions. Her situation was unique based on the fact that Picard wanted her there.... you don't see counselors on the bridge of every starship do you? If Picard wanted her off the bridge, it would have been done.
Another issue with Deanna was her willful use of impathy to read others thoughts.
That's what her species does and comes to them as fluent as us blinking. If you don't like what they do, then when you get your own starship command, you can choose to have no Betazoids on your ship if you so wish..... but that'd be prejudice.
That can be considered a violation/ mind rape. She herself hated it when she was at the receiving end of a mind read.
Once again, you're completely wrong.... sensing someone's thoughts as they come to you is one thing.... having someone shove their mind inside your own to force you to have visions or voices you don't want in your head is a totally different thing.
What she was capable of doing isn't much different then us looking at someone's facial expressions to determine someone's mood.... the only remote difference is she could determine someone's mood even if that faked their facial expressions. If you don't like what she could do, then you obviously don't like people in your everyday life determining your mood by looking at your facial expressions.... if that is the case, may I recommend you cover your face with a Burqa or Halloween mask?
The good thing about B5 was that it brought up a different perspective on telepaths. It went into how telepaths had to restrict their telepathy to avoid absorbing the thoughts of others. They were also shunned because non-tels were afraid of getting read. In TNG, those issues seldom ever came up. I will admit that Voyager did visit that topic in its later seasons.
That just sounds to me like someone with a mental or physical handicap having issues with others being able to do what they can't and thus forcing everybody to live like them.
ie: let's say I was born without arms but you still have yours, you can draw, write, build things, etc.... but because you have an advantage over me, should I have the right to argue and complain that you should restrict your life and who you are to suit my own hang ups?
No.
Hypothetically speaking, people born telepathic should have every right to use their abilities to their full potential as they see fit, considering it is a part of who they are. To restrict them because of others being uncomfortable isn't much different then our own history where religions would restrict or otherwise oppress people who brought out differing ideas or concepts.... or they lived their lives in a different way that made them "Afraid"
While this may make the over-sensitive comfortable in keeping things as they see fit, it only restricts the progress and development of society and the individual themselves..... all because some people don't understand something and are too scared to take the time to understand.
I remember the episode when the Ferengi were negotiating the rights to a wormhole and a Human/Betazed negotiator was using his skills to beat the competition. When his skills were discovered, Picard blasted him for using his telepathy for his advantage. The negotiator made Picard eat his words by pointing out Picard's own hypocrisy of using Deanna for his own gain by reading the minds of others. Cobra
Indeed.... however I personally had no issue with him being telepathic and using it to his advantage, the only thing I didn't like was how he avoided telling anybody about it and trying to act like something he wasn't.... which seems to be your entire argument (ie: restricting their abilities and/or trying to keep them hidden from everybody else to make them comfortable.)
He's a perfect example of what could happen if one followed your view. Others being afraid of what he can do and thus forcing them to abide by laws or other restrictions to make sure they don't use what they were born with, will only create more people like him who have these abilities, but refuse to tell anybody, thus never having to worry about breaking any laws or restrictions, because nobody would know he had them, thus be more alienated by the society around him and thus using his abilities to his own advantage rather then everybody elses.
Afterall, If I was in a similar situation, I know I wouldn't expose my abilities because of such restrictions and laws, I would feel like society is against me and my kind and I'd probably end up using my abilities to further excel my own goals and the goals of those like me.
A perfect example of what happens with such views as your own would be to watch the X-Men movies.
Oppress those whom you feel are better then you, and you will only turn those people against you.... which is what Oppression has always done....
Oppression never solves anything.
Added:
Also, I forgot to add that considering the size of the ship, the total amount of crew members & families on the ship and the fact that the ship was designated for space exploration and being away from home for long periods of time, having a ship's councilor made pretty good sense to me.