Why is there a noticeable gap between Casters and Melees?

[Sentinillia]

The close argument doesn't sound, well, sound in my head. They don't have to dodge much mechanics, or at least in final coil, comparative to ranged. The ranged deal with the same mechanics.
Note that I'm not asking for a buff, just sounding my irritation that the fights are always so stagnant and... plain. Why can't phases of a fight favor different job styles? Why can't there be more ranged/melee specific mechanics?

This was addressed already:

That being said, the current FCoB mechanics do not follow this path. They are all very melee friendly, which has lead to the gap between the DPS classes being very VERY noticeable.

Melee is very strong in the Final Coil. Such was not the case in Binding/Second coils. Take t7 and t9 for example. In t7 melee DPS have to disconnect from the boss everytime Melusine casts the aoe move around her, or even worse, they get Shrieked.
T9 was riddled with disconnects, spread out targets and things that forced you out of position on the boss, making you unable to hit the directional sweetspots.

Rather than adjusting the jobs any further, they should focus on making fights that cater to both jobs equally, or a multitude of encounters that have different preferences for DPS jobs.