This is an essential feature for me. I've added my voice to a forum post before (2 or more years ago?), requesting that the feature be migrated from Evernote Legacy to the new Evernote. I am also one of those people who use The Secret Weapon / Getting Things Done system, which rely on the sorted tags, where the tags are listed in alphabetical order per note.
This is now even more urgent for me, because my copy of Evernote Legacy has just been overridden by the latest version of Evernote, without warning. I will attempt to get Evernote Legacy back shortly, but if I can't get it back, I can't justify the upcoming Evernote price increases.
Evernote, please bring back alphabetised tag sorting as soon as you can.