There doesn't seem to be any technical reason why its not a good idea, people just don't like the extra work and are lazy I guess. My take is that gear swaps in general are so buggy and slow it would be practically pointless to macro them for certain WS/spells as you did in FFXI. The current game engine is just so laggy, poorly designed.

The more annoying restriction, to me, is not being able to change your class (at all) when you're under attack. Previously when I was MIN/BTN I could quick switch to DoW if I was being attacked. Now I just get beat on until I run away or die. I really miss that one.

Originally FFXIV allowed gear change in active mode right? I can't remember, so many changes since launch its a blur.