I personally prefer option 2. This "Going with option 4 being for the French/German player base" thing- I'm sure a good chunk of those people this is all for won't even end up on server 10 anyway. There is not really many cons since well, the naming system in this game makes it much much harder for people elsewhere to have your name unless you were lame and named yourself after a popular game/animu/movie chara. It Also helps returning players at least be able to reunite with friends easily, and not get their mules scattered across worlds.
To people comparing it to FFXI's server merges as a con- (I only skimmed and noticed a phoenix/titan comparison) you cant compare it to the Pheonix/Titan merge. That server was well, shall we say home of some pretty hardcore players compared to Titan. Titan was well- more of a casual server. Even Phoenix's casuals were considered hardcore to their standards- hence why they would feel that way. ( You could honestly tell people who was from where just by gear alone lol ) But compared to that, this game is still in primal stages. I know this prolly was the case for other servers too, but take into consideration that the communities here aren't as tight as FFXI's which had people who played together for a good couple of years. many of us were together for a year and a few months at most. Also, the server elitism that existed in XI wouldn't exist due to lack of content.
and honestly the other server i was on when it merged ( Quetz x midgar ) while I was against it for the sole reason of quetz's food market ruining my gil income- the communities blended together well. For XIV, market crash is something that isn't of concern. The markets are meh to begin with due to this game's age. lol
Honestly though, option 4 doesn't bother me ( it's easy to figure out where you and your friends will go- it's how most of us got to x server in the beginning anyway ), but it has many cons to it. Ya wanna be with your friends, server full and only half your friends got in? Too bad, your SOL! Got a mule and it didn't make it to your server? Oh wait your SOL! Come back from that long wait for 2.0? Oh wait, your SOL and lost not only your group who would letcha back in (not like many of us are doing much together since a lot of us have everything lol ), but your mules too!
SE... if you go with 4, at least make sure inactive characters made before the merges have 1 free transfer credit that they can use upon reactivation. You will lose many of those people waiting for 2.0 to come back.