Wow, these 40 pages were quite an enjoyable read. I would like to make a contribution.
Personally, I would transform TK into the following buffer skill:
Tornado Kick: Weaponskill (Cooldown: 15s)
If the last three weaponskills used had the same directional requirement, executes Light Kick.
Otherwise, executes Shadow Kick.
If any of the last three weaponskills used had no directional requirement, this action is unusable.
Light Kick: Delivers an attack with a potency of 300
Shadow Kick: Delivers an attack with a potency of 100.
Additional Effect: Damage over time
Potency: 30
Duration: 36s
If the 15s cooldown is affected by Greased Lightning and SkS, it should be usable every odd rotation. I think it ties nicely between the Coeurl and Opo-opo skills. It also fits slightly better with the lore of the 50-60 job quests. Obviously, the potencies would have to be tweaked. And something would have be nerfed in return.
