Well someone pointed out that "hey why not just unlock the other job you want to play on the same character?"
I disagree and here's why: I picked a miqote' (keeper of the moon for the nice stats in mind and intelligence). Their starting stats for INT however may be somewhat lacking for THM/ACN/BLM/SMN. You'll notice a trend here and that's my preference for making characters that fit a little better into their roles stats wise. With that being said yes I'm going to have at least 2 characters; one to play melee jobs and one to play my Mage roles.
It was disappointing, to the say the least, when I found out I couldn't mail myself any of this awesome gear I've gotten for my melee classes.
While I totally agree with you from a min/max or RP perspective, I think it's important to note:
Ultimately, as long as you chose appropriately and build properly, the small differences in starting stats accounts for much less than a 0.5% difference end-game.