
Flourish doesn't work too well for warriors because a majority of their attack skills were adrenal based or had extremely short recharge times anyway. However, Flourish is much more usable for assassins considering their lengthly dagger skill cooldown lengths.
Here's a sample build that can use Flourish:
1- Unsuspecting Strike (fast recycle) or Leaping Mantis Sting (lower energy cost)
2- Wild Strike (fast recycle)
3- Horns of the Ox
4- Falling Spider
5- Death Blossom
6- Flourish {E}
7- Shadow Refuge
8- Return or Critical Eye
The above build can perform chain knockdowns and abuse Flourish to recycle Horns of the Ox or Death Blossom. For the above, you could use this skill sequence:
Unsuspecting Strike -> Wild Strike -> Horns of the Ox -> Fallng Spider -> Flourish -> Horns of the Ox -> Falling Spider -> Death Blossom.
The important thing is to use as many 5-energy cost attacks as much as possible, since you'll be executing roughly 10 non-stop high damage dagger hits (1 lead, 3 offhands, 3 dual attacks).
I've also started experimenting with this endless energy build:
1- Mirrored Stance (or any other hex you like)
2- Critical Eye (optional due to Black Lotus Strike)
3- Black Lotus Strike
4- Horns of the Ox
5- Falling Spider
6- Critical Strike or any other dual attack you want
7- Flourish {E}
8- Shadow Refuge
Flourish effectively reduces Black Lotus Strike's recharge cycle from 25 seconds down to 10, thereby prepetuating the assassin's available energy. It also recharges all dagger attacks, making even more enticing.
Flourish also negate the effects of Disrupting Chop, Diversion, or any other skills that can normally cripple your dagger attack sequence. Moebius Strike does offer some similarities to Flourish, but it's not nearly as flexible. Assassin's promise requires a kill, thereby making it a little too situational as well.
Flourish does have potential when used by assassins... it's up to us to figure out the rest of the possible combo's.

Credits: /raises hand...