I'm going to have to disagree with the "need" of this.
While a lot of points here are valid, such as maybe the name is just an old name from 2 years ago, and they can't be bothered to pay for a new one, I can see this being abused.
Here's the thing - I understand that you said just moderators would be able to do it. Sometimes, our moderators do like to have fun (shocking!), and sometimes that gets out of hand. To prevent this, we simply don't give them the chance to abuse something.
Yes, there are ways around it, and we could most certainly get a real name out of a fake name very easily via the plugin, but I don't think it's worth having this command or the ability to.
In short, it'll be abused one way or another - it's the sad unfortunate truth, and I'd rather not implement something that is going to be abused when we could've been working on something much more productive.