I like multitenant because it may be a good idea to give PDB DBA rights to the application owner (at least in dev/prod) so that they manage their database. But I can't do that for the moment because a PDB admin can create datafiles anywhere on the server, and that can be very difficult to manager.
A good idea would be to constrain a PDB to a specific directory (and subdirectories), so that all related files (datafiles and tempfiles) cannot go elsewhere. Then the CDB admin can give admin access to a PDB with the guarantee that he will not go outside of the assigned filesystem. Should be available for ASM as well.
I've seen a PDB_LOCKDOWN undocumented parameter that appeared in 188.8.131.52 but I don't know if it is related to that. But would be a good name for it