For those to be viable, fights need to be designed very differently. Proc based mitigation works best with fights that have a constant mostly stable stream of incoming damage where the
Law of Large Numbers can take effect. It does not work with the very spike heavy tank buster focused fight design of FFXIV.
And then you end up with fights that are less mechanically complex and more based around dealing damage as fast as possible. The Trinity role division system actually allows fights to be more complex.