My apologies - I confused it with a similar issue but not for the EX2 Public share but for the shares of any attached USB hard drives. I just checked in the release notes ( http://support.wdc.com/download/notes/WD_MyCloud_EX2_Firmware_Release_Notes_1.04.05.pdf?v=4646 ) and if you scroll down to page 4, you will see the 4th last item from bottom is what I had in mind. Which obviously is different from what you were looking for. And perhaps I didn’t catch it because I do use an smb hack (that I wrote a HOW-TO article here somewhere a while ago) and forgot that this change was never implemented in a firmware.
I guess you can vote for a long-pending request submitted on this board by clicking on the up arrow to the left of the post - tha registers your vote for this request → http://community.wd.com/t5/Network-Product-Ideas/Delete-Public-Share-Folder-or-Restrict-Access/idi-p/702110 . It has been In Review status fr a while - which means WD is already considering implementing it (which means it already garnered enough votes - but doesn’t hurt to still vote for it…I voted a long time ago myself.