I'm thinking that if this change is legitimate, it is serving the WTS more than anyone else. As always, the rule to FOLLOW THE MONEY offers some insight in this Adjustment™.
For example, suppose Elder X is found out to be a child molester. His appointment by the Circuit Overseer™ will provide a buffer against any liability that the WTS has.
The Circuit Overseer™ having taken a Vow of Poverty™, will not be able to pay any damages to victims of Elder X. And because the WTS did not Appoint™ Elder X, they have no financial liability if damages are payable to the victim.
A word of caution to anyone who is named as a trustee of any Kingdom Hall™: Protect your assets. If any member of your Congregation™ is found criminally responsible for a crime and that crime has to do with defrauding other members of the Congregation™ or using their position within the Congregation™ in order to defraud or victimize members of the Congregation™ (or even a JW with access to protected medical information who uses such to inform on another member of the Congregation™), as a Trustee you can be held financially liable if damages are payable by the Congregation™.
The way I see things going, the WTS counts all Kingdom Halls™ among its financial assets (it charges RENT in perpetuity, after all), while the Trustees are named, more or less, as legal custodians for the day-to-day affairs - maintenance, utility bills, etc. It always seemed to me that the people named as Trustees have some measure of financial security - they own their own homes, they have businesses or a good income. It seems to me that people in the position of Trustee may not realize the financial peril they put themselves in should a lawsuit ever arise against the Congregation™.