I stumbled upon this topic by chance, and it made me want to try some stuff using the "/hotbar Action" function and share some macros I came up with. I haven't tested them in real combat situations (only on a dummy), and they are NOT viable if you want to be really effective at your job, but who knows, someone could find a use to them, or make them better.
1st type of macro: Ninjutsu for the forgetful.
Examples:
Katon:
/micon "Katon"
/hotbar Action "Chi" 6 10
/hotbar Action "Ten" 6 11
Doton:
/micon "Doton"
/ac "Ten" <me>
/hotbar Action "Jin" 6 10
/hotbar Action "Chi" 6 11
My initial intent was to make one-button ninjutsu macros without a "/wait 1", but I found it wasn't possible. Instead, I came up with the idea of a Ninjutsu-only hotbar, which looks like this.

When you click a three-steps Ninjutsu, it executes the 1st mudra immediately, and changes the last two slots of the hotbar (hotbar 6 in the example) to the rest of the combination in the correct order. Two-steps Ninjutsu work similarly, but clicking the macro does not execute the 1st step. This is so that the last 3 slots of the hotbar are always correct.
The One-Slot-But-Not-One-Click-Combo.
Example:
Aeolian Edge Combo
/hotbar Action "Spinning Edge" 6 2
/wait 2
/hotbar Action "Gust Slash" 6 2
/wait 2
/hotbar Action "Aeolian Edge" 6 2
/wait 2
Once you click this macro, no action is executed. Instead, the 1st step of a combo of your choosing appears in the slot you chose. 2 seconds later, it will change to the second step, and 2 seconds later, in the 3rd step, all in the same slot. If your recast time is lower than 2 seconds however, you'll waste time. Unlike regular full-combo macros, queueing/spamming/whatever is possible, since you are not clicking the macro, but a regular ability. It looks like this: