I personally see room for improvement for the level 60 monk skill, Tornado kick. I understand the philosophy behind it's design where the design time wanted us to utilize our GL3 stacks to deliver a all-out attack between boss phases such as using TK during Ravana's liberation right before it disappears, etc. And to be honest I have absolutely no issues with that.
But as it stands right now it doesn't have a steady niche as a level 60 skill. As much as it sounds good on paper, there are issues with it. Mainly because of the difficulty in maximizing it's usage in certain boss fights. More noticeably in the new raids, namely on Faust from Alexander Savage and pretty much every floor of Alexander normal because of their "unpredictable" phase switching and the "survival-mode" mechanics introduced into the new raids.
Alexander floor 1
Glaring issue during the boss phases when the 2 oppressors jump into the air to do their area-wide attack. Unlike bosses like Ravana where they show a cast-bar right before it does it's attacks so you know when it's going to phase-change, the oppressors just jump. Without extensive research and note-jotting it's difficult to time a perfect Tornado kick before it jumps to properly utilize TK.
Alexander floor 2
Issue is in the fact that it's pretty much a "survival-mode"-like stage where you just have to do DPS hard and attack the right targets. Which makes TK completely useless here as you are constantly trying to keep up GL3 and it makes no sense to want to drop your GL3 for any reason at all.
Alexander floor 3
Similar to A1 except that the issue is much more obvious here. Mainly during it's several phase changes which is near impossible to time properly. At times it phase changes to the hand at about 85% HP, at times it's 81% HP. The same can be said for the the hand>Tornado hand phase where the change can range for a wide variety of HP % numbers.
Alexander floor 4
Noticeably during the first leg phase and the annoying "disappearance act" mechanics. There are several openings during phases that can allow TK to further increase DPS such as the part where the Manipulator becomes available to be attacked for a short while before it does it's aoe attack when you destroy the first leg. Similar to the previous floors, the boss doesn't display a cast-bar before it does it's attack which makes it untargetable. So you have to roughly gauge the timing to use TK which can range from 85%-80% HP which is a pretty wide range. If you were to execute it at 85% HP, you will do much lower DPS for the remaining 5% or less on the Manipulator as you will have lost all your GL3 stacks overall affecting your DPS. The mechanic where the Manipulator throws you and a tank into another room with an add can affect your overall DPS as well since it causes your to pretty much lose all your GL3 stacks most of the time. It wouldn't be that bad if you know that you are going to be thrown into the room as you can TK the boss right before it throws you but sadly it doesn't.
Faust from Alexander Savage
Pretty much no usage from 100% HP until 1% HP. It also has a pretty long animation time before the damage number applies. In a clutch fight like Faust, the animation delay can either seal the deal or break it. Many times we got Faust to 1% HP where something like a lucky crit from TK might have allowed us to pass through but the animation delay and the fact that it is only effective when the boss is at about 1% HP is making the skill a pain to use.
Alot of the issues go against the design philosophy that the Yoshida mentioned. Yes, the design would have sounded good on paper, especially in boss fights like Ravana EX where you can time TK perfectly and utilize it to it's fullest. I guess another way to look at it is to blame the design team for not adding cast-bars to the boss skills. A good example of bosses where you can properly utilize TK are basically all the primals available. Titan, Irfit, Garuda, Ravana, Bismarck, etc. All of them have some sort of cast-bar for their phase-changing attacks which is what monks need to properly utilize TK at the right timing!
And also I do not think that the 5 examples mentioned above are the only ones, I believe there are more of them as well.