Originally Posted by
Zenion
That one's not really on the equip sets. When you hit a macro, the game's executing all the commands in the macro in order. If you hit the macro again before that's done, well, gotta flush that last macro hit from memory to run the new one, or else risk some really stupid behavior (potentially unlimited action queues which could hypothetically be used for functional botting, or worse just cause enough input spam to destabilize the client.)
To have the game actually intelligently determine which set of equipment you want to be wearing at any given time, you would need some sort of, I dunno, gear swap management engine, which is certainly theoretically very very possible to implement, but not necessarily in a way that could be integrated with Final Fantasy XI's engine.
I mean, it would be really cool to have a prioritized tree of gear sets to use with each spell and have them micro-managed; it would especially be nice if this could be done in a way that would fix the horribly annoying "you can have quick magic or potency gear but not both" dilemma from equip set cooldowns. Moreover, it would be a move toward making vanilla FFXI do some of the things that people keep choosing modded FFXI for. But I think this is one of those issues where the devs are going to just lean toward "git gud", managing your own gear swapping is a part of the game.
Just be thankful you don't have to hit ten macros to execute the appropriate gear swaps for one command any more.