I think a name change would be a good idea, but there are two problems.
There must be a way for people to prove what their previous name was. Say I, as Jake408, get my name changed to Jake. All of my friends would now have me as Jake on their friends list.
Now somebody else, say their name is PVP0WN4G3, changes their name to Jake1. All of the friends we have in common would now have both Jake and Jake1 on their friends list. There must be a way for me and PVP0WN4G3 to prove who we are.
I saw in a previous comment that people are distinguished and known by their gear and fashion. This is true...but really only for high levels in end game clans, but that is not the portion that this problem affects. This is mostly for the mid and low level players, who often have the same gear.
Another problem is scamming. This can possibly be made somewhat better with a way for people to prove who they are, but scamming will still go on. Say that some high level player is at first named Shadowstrike, and all of his friends know him as Shadowstrike. He then changes his name to Fred.
Now somebody can change their name to Shadowstrike and scam players.
Now you may think....well just look at his level and clan and you will know the truth...but thats the thing, scamming goes on today BECAUSE people don't look at level and clan, and a name change feature will not change peoples awareness of scamming.
There is no problems for Alexandre49 to Alexandren, AIexandre or ALexandre. (Already used on Danu by me

for copyright )
If we can change name once at lvl160+ there will be no problem, maybe we must keep 50% of our letters.
A scammer who change his name to a old player name or scamm will be reported and get back his last name or account blocked. When you are 160 you dont want to have done 160lvls for nothing so it will be ok.