I agree with you on the whole use of account names. It means, for one thing, that if I see any of my guildmates or other freinds in game I will have no way at all of actually telling them apart from any other player. It would be better if they used your character name with the account name in brackets. Then you can see which character someone is on but can also relate that character to an account/ individual person as a whole.

Well, since guild membership, as in GW2, is account wide then knowing which account a character belongs to is important for some purposes so I think the problem really is that the character name isn't used at all, so to that extent I agree with @wenxue2222b16_ESO.

As for 'hackers', I'm less worried since I always have to assume my account name is vulnerable in any number of ways so what's protecting me is my password.

The visibility of account names opens us up to DOS attempts by someone deliberately trying to login with the sole intention of exceeding the attempt count and getting us locked out of the game.

On a lot of other mmos iv played , when starting a different character it's not hard to just let people know it's you. "Hey guys it's me ,xxxxx, started a new character " that's all I ever did in WoW and it worked out fine :S