Thanks a lot for this feedback, Celia.
Changing the behavior of such relevant code should be discussed and handled with care because it leads to big impacts. Customers started with Pro/INTRALINK used PROI_CREATED_BY. Now it is called PTC_WM_CREATED_BY and customers have to enable dm_emulate_ilink_sys_parameters = yes to reuse their legacy migrated data. In ProductPoint is was named different again. Why?
In some locations around the globe it is restricted by law to keep those information on the drawing for years. That's why it is a realy big thing!
Some notes to your developer team:
I also came across those issues you described above and used some methodes to workaround them by calculating the expected user name using user.getFirst, user.getLast, aso...
But it is not realy good practice to mark code as deprecated (>=10.2 F000) and simply return "null" at the same time instead of removing it completely (even if those methodes are not part of supported API). If the result of those methodes are invalid why keeping them in the code. FMPOV deprecated code means that the result is valid but it is planed to change or remove in the future.
Customers and VARs do not recognize changes like that while compiling the code and run into trouble at a very late state.
Please remove methodes like user.getFirst if the result is not usable anymore.
Hopefully you will find a solution to satisfy all customers.