I still say the only game you can really point at when you say "long dev times" is Versus XIII, which in the end was vaporware anyway. XV was available 3 years after announcement, World of Final Fantasy..I actually don't know but that can't have been more than 1-2 years either. XIV churns out a top-notch expansion every 2 years.

You could make an argument that the mainline entries are too far apart now, but who knows, maybe they'll get that back on track with XVI. If they bother making it.