I see no problem wirth it. I would if I could not change the drive, which might be an issue if my C drive is almost full. But I can change the drive,. The location where the resource database lives is always on the same drive where the data files of the instance are installed, but in a hard-coded path.

Asking to be able to move the resource database is, to me, like asking for the ability to move two or three of the DLL files in <drive>:\Program Files\Microsoft SQL Server\<instance_name>\MSSQL\Binn to a different location - I don't doubt that people will be able to come up with a use case, but I still doon't think it's worth the bother.

(And I chose the Binn directory on purpose for this comparison, since most service packs also replace some of the DLL and EXE files in that directory, just like they replace the resource database with a newer version).