When we had a look at the new job actions from the liveletters and previews, I was excited to see an action on the GCD that had a unique effect on recast time. I am not a Monk main, but seeing this skill made me think of how interesting the Monk rotation could be in Shadowbringers. For example, it could have been used heavily if Monk still had numerous abilities that had to be weaved in a short timeframe. Instead, Monk had 3 abilities (Steel Peak, Howling Fist, Internal Release) removed and the majority of the rotation has been changed to what it was prior to Stormblood.
Clearly though, based on potency numbers, Six-Sided Star was not meant to be fit into a regular rotation. The skill takes up the length of 2 regular GCDs, and there is no pair of GCDs in sequence that Six-Sided Star overtakes in potency (whether it be Dragon > True Strike, True Strike > Snap Punch, Snap Punch > Dragon Kick, or Snap Punch > leaden Bootshine). Monk is pretty light in oGCD abilities this expansion, and all of the abilities it has can easily be singled-weaved. This means there are only 4 clear situations where it should be used:
1. If you are not in the tertiary stance and thus have no other way in 3-4 seconds to refresh your GL stack timer.
2. Before using a Limit Break.
3. For shorter disconnects from targets for a fight mechanic, etc.
4. Just before a target dies/goes invulnerable and you want to combine it with Tornado Kick for an extra burst.
It could also be something to consider before a raid buff runs out, like Trick Attack, etc., so you get a heavy hitting 400 potency attack in that window, but that is something I'm not sure of.
I think every player who learns Monk experiences it like a puzzle that has to be solved. However, the rotation seems like it has been mostly solved by experienced Monk players. Still, like the Tornado Kick rotation that was found in Stormblood, there could always be either future discoveries or changes that can make the class more fun.
I am still learning how to play Monk more effectively, but in the future (particularly with possible 5.05 job changes), I would definitely appreciate (and am almost excited for) changes that would make not just Six-Sided Star, but Tornado Kick and other skills, see more use in the rotation. As it is right now, I am not particularly interested in perfecting a 4-6 year old rotation with server tick shenanigans involved with Anatman.