unless they rewrite the game from scratch, there will always be old code lurking around, which is generally meme'd as "spaghetti code"

I am not a dev, but I support software, and what I currently support is something that was expanded from something developed in 2010, so about the same length of time as FFxiv. A major problem is old code bits left around which are always causing issues. are the devs using it as an "excuse"? I doubt it, its reality, and rooting it all out will never happen without a complete rewrite, which I doubt they will do since for an mmo, would likely entail more resources than they can or want to spend on the game. current FFxiv may not resemble 1.0, but its built from it, so will always be with it. they can try and mitigate it, and add new systems on to it, but the unfortunate reality is, some things they may not want to touch because changing it, may break more things in game and they, or we, can imagine.

doesnt mean they cant try, and they may have, we will never know. but in some cases, implementing some new feature might be more like trying to erect a skyscraper on a mudflat. not ever an ideal plan.