I was against the whole first-last name thing at launch; it did seem cumbersome especially if you had to use text commands to invite someone or such and needed the exact spelling for both their names.

Thinking about it now though, I've found very few instances where this is necessary and having last names can be fun!
For example, in my linkshell, their are a few couples that play together (myself included) and their characters share the same last name.