Absolutely true, but the upper level design talent is also a finite group of people, and they can only do one thing at a time. Hiring two teams of programmers isn't nearly as difficult as hiring two high quality game designers.
In terms of sense from SE's perspective I agree 100% with naming it FF14. Having it as a numbered FF will increase sales prospects significantly. Ultimately it is SE's game, and I have no objections to them doing what they want with it. I was just voicing reasons I thought not having it a numbered FF seemed more appropriate to me.