problem is sometimes name changes are for the purpose of changing personally identifying info. There’s no point in changing a name to hide a real name or email address if that’s then displayed publicly. Witness protection isn’t that far of a stretch for an analogy
So if there were a public indicator it’d need to be opt-in for privacy reasons
99.99% of people now are just changing for the hell of it. every week there's a new "imposter" in my guild - and I give up keeping track of the changes in friends or other guilds. In the previous 7 years of play I knew of 3 people total who had used full or part of their real name and asked support to change it, and 2 people who were forced to change by support because their names included a website or inappropriate term. That's not even 1 a year, and now it's every week.
Privacy issues are used as an excuse for poor thought and execution. People post much more security risks on their social media pages, like pictures of their house and family, where they work or go to school, which is personally why I avoid social media, but really - a game name is the big risk? No, I don't buy that.
If players didn't mind everyone seeing JRoberts77 for a year when they decided to use it in the first place, they can live with everyone seeing it for a week or less as a town hall notification that it changed. This is a half-assed implementation and has blown a hole in game integrity because we can't track our friends and enemies while their names keep changing. One of many holes created in the past year, and playability is not being considered.