The bar for Island Sanctuary and Criterion Dungeons are very high

[Shibi]

I feel like their biggest mistake was hyping up the feature before Endwalker even released as something major...

Biggest mistake was shuffling Yoshi and other senior staff off to work on FFXVI and handing over XIV to the interns and contractors.

[Garnix]

Biggest mistake was shuffling Yoshi and other senior staff off to work on FFXVI and handing over XIV to the interns and contractors.

That's a bad take.
1) Senior staff working on the same project for 10 years might get burned out of working on the same thing for so long, with the same pipeline, same methods etc. Better to put them on another project before their desire to produce good content vanishes.
2) Newcomers can bring breath of fresh air to the team, and to the game, because they have not been in the 'FFXIV development tunnel vision' for 10 years.

They need to keep a balance between both. That's healthy.