So, to summarize: "Making it different would make it different, and different is bad."
That's not a problem with porting it to a different engine, that's a problem with people deciding to make changes while they're in there. It shouldn't be impossible - or even difficult, necessarily - to rebuild FFXI on a new engine in a way that make it still look and feel largely like the current game, only better (shaking off the last baked-in PS2 limitations like macro length, data transfer rates, and the like.)
I wouldn't particularly enjoy "FFXI-2: Now It's Just Like FFXIV" either, but a team that cares about what they're doing can remaster a game without ruining it.
