I understand the arguments for having access to multiple alts, but personally I think the focus on a single character is refreshingly different from other games in the genre. It may also lead to players acting with more civility to each other*, since reputation becomes more important without the anonimity provided by having easy access to a dozen alts.

*I understand you can still buy alts that people can and will find ways to be jackarses to each other, etc. etc. This is more of a theory based on my personal experiences with people in FFXIV than anything.