Just a remind for you,
There is a free battle.tag nickname change. I would not cancel, obviusly, my blizzard account but I would not put my old nickname because reforged is what is is.
So… just changed my battle tag! For free! (once) So is up to you if you want be knowed as ppl knowed you in old good days or… other thingys 
Have a great day.
you can only change it once for free, then it costs 10$ per change.
I know 
Would edit OP for not missleading.
Awesome! Instead of just changing my battle.net name which was previously super easy, I now have to pay $10 to use my old custom map saves on things like Twlight’s Eve.
$10 to use stuff that I already had and paid for two decades ago.
THANKS BLIZZARD!
If you really wanted to, couldn’t you avoid the $10 fee of changing names by making a new battle.net account and moving your Warcraft 3 license over to that account? Or is that not possible? You’d also have to re-register any friends you have.