should a publisher just trust that their local elders will only write positive and accurate things?
If the individual doesn't trust the elders, he would not sign it. By signing, he gives his consent that the elders are free to write what they want. The form is given to publishers in good standing. If the elders write inaccurate or negative things about the publisher, they are making a jackass of themselves as the branch would ask them why did they even give the form to the publisher who has questionable habits.
The following para appears on the A-27 form before the applicant's sign:
I further consent to the branch office of Jehovah’s Witnesses that administers the activities of Jehovah’s Witnesses in my geographic area processing and retaining for its use the information found on this application and any additional information that may be submitted in connection with my application by individuals serving as elders of Jehovah’s Witnesses
Are the 3 men making up the Service Committee always impartial and objective - in every congregation?
That the individual has to decide how his service committee is and then decide if he wants to fill the form and submit the data. If the service committee if filling negative data about the individual, the branch or the CO directs the elders to speak to the individual why his application has been rejected.
Is it healthy for the subject (the publisher) to be denied access to see what has been written about them, and available to view on the new Publisher ID global JW database?
Sorry didn't get this question. What information is collected on the new database which the publishers are denied access to?
I’d like to know: should I be worried
The WT has been collecting information like these since decades. Do you have any evidence where WT has misused this information for commercial or non-commercial gain? If yes, it would be interesting to know.
If billions have chosen to trust Mark Zuckerberg with their personal data, then I don't think 8 million witnesses who trust the FDS more than their life will doubt the WT (when more then 75% of the member's data would be only name, address, and dob.)