This has bugged me for quite a while.
There is a ton of gear in the game that is blatantly made to be equipped before you cast a spell, and then gear that is made to be equipped as the spell is being cast for max potency of that spell.
However the game macros have a cap of 1 second and so usually you can't take advantage of this gear well.
This is gear that is effectively made for cheaters, there really needs to be some fix made so players can actually use more complicated precast gear without having to resort to cheating.