The Egi Glamour system being stagnant has nothing to do with the system itself being hard or time consuming and everything to do with the fact that models, animations, and visual effects for Ramuh, Shiva, and Leviathan Egi don't exist and would need to be made. The actual system itself is incredibly simple and fast to make. The reason they don't want to put in the time to create new egis for cosmetic reasons is because that benefits exclusively the Summoner job. Meanwhile a system where you can choose which version of an action in an action tree you want to use is something that benefits every job that has any actions that get replaced by new ones at a later level. I can tell you the healers would appreciate this as well.

And the point of the system is to make it so that rather than spending time making additional assets for the Bard job that would require man hours that would otherwise go elsewhere, you just use the time already allocated to making whatever actions Bard is getting in 6.0 to be all musical-themed, but with a system where if you don't want to be a musical bard, then you continue using the old animations for whatever's getting replaced (Bloodletter, Rain of Death, Sidewinder, etc.) In short, no extra time that's not already going to making Bard's 6.0 actions will be used to make any additional assets for this one job alone and no others.

Also I have no idea what a random lore excerpt has to do with the proposition of a simple game mechanic.