So, I've recently took the quiz on my alt account (Not THAT recently). and I've noticed that when Oak says "What's your name?", He doesn't clarify if it's your first name, or first AND last name. When people do think that he means both names, they end up with something like "Jackwhite" or "Sarahfox", and they don't get another chance to change their name.
Basically where I'm going with this is to change the wording of what Oak says, to clarify that when he asks for your name, he is asking for your FIRST name, and that you can correct your name if you mistakening put your first and last name, or if you make a typo in your name. I think that would save a lot of time for name changing.