Agreed... I never thought about it after years of brute force with it... the good news is you can have multiple shares to the same target...so you can create the new then delete the old, but a rename would be a nice to have feature.
Got tired of the manual steps to rename and found frequently needing to rename cifs share. Wrote the below short script tonight to rename a cifs share, preserving the access permissions and any comments. Other settings are not preserved. This script requires linux/perl and ssh pki authorized_keys equivalence to the filer. This could be converted to probably any OS by changing the $err_file path in sub run_cmd. The $err_file path is to simply capture STDERR as the script performs robust error checking for each ontap command.