How good is the game engine of FFXIV?

[Enkidoh]

The thing to remember is though, one of the design choices Yoshi made when developing ARR (and thus the choice of game engine), is that FFXIV 1.0 required (for the time) extremely steep hardware requirements to even run properly let alone look good, and that in order to gain the most widest possible audience for ARR (as a means of reestablishing good will with players), the new graphic engine for ARR would not have such steep requirements. It still looks good (compared to say, old MMOs like FFXI), but it's a case of you can't have your cake and eat it too - it's the nature of the beast, a slight graphic fidelity drop in return for more detailed zones and more interesting armour design (as an example). So the RR Luminous-inspired custom engine does have some slight reductions compared to 1.0's Crystal Tools.

I think you're not going to see a massive restructuring of ARR's engine, in that SE are more likely to simply make a whole new MMO with a more modern engine, that's just being realistic.