I kind of feel without him the game is likely to become even more same-y than it already is.
He at least has potential to try new things occasionally
A new director is likely either be too timid to mess with S-E's money baby making it stagnate even more than it has already or take crazy wild swings that end up hurting the game a lot.
Honestly I think the way FFXIV is basically S-E's lifeline is making the whole company scared to mess with the formulaic nature of it
I do kind of long for the FFXI days where every new thing was some insanely different content just about every time though so maybe a risk taker would be good