First, again, the following examples are just a thing that came out of my mind, and I am considering that no skill potency will be affected by positionals, since imo thats sad and boring, so a NIN that does no positionals is the same NIN we know.
Okay, so, lets take MNK's positional mechanics first:
MNK positionals doesn't really spin around their weaponskills, but the form that are triggered by their skills.
If it were simply based on their weaponskills you would be able to critical Bootshine or apply Dragon Kick from the get-go, which isnt the case.
Nope, positionals for MNK actually spin around the forms Raptor, Coeurl and Opo-opo.
So actually MNK opener goes usually: Activate Raptor > Raptor Flank > Coeurl Rear > Opo-opo Flank > Raptor Rear > Coeurl Flank > Opo-opo Rear.
How can this work for NIN?? Well... lets say that the skills Spinning Edge, Gust Slash and Aeolian's Edge have positionals.
Spinning Edge Flank -> Huton + 3s (cant go higher than 70 seconds)
Spinning Edge Rear -> Dancing Edge + 3s (cant go higher than 20 seconds)
Gust Slash Flank -> Dancing Edge + 3s, DoTs +1s
Gust Slash Rear -> Huton + 3 seconds.
Aeolian Edge Flank -> Huton + 3s, Dancing Edge + 2s, DoTs + 1s.
Aeolian Edge Rear -> Dancing Edge + 3s, Huton + 2s, DoTs 1s.
So if we want to boost Huton we would need to go SE Flank > GS Rear > AE Flank.
Or if we want to boost DE + DoTs we would need to go SE Rear > GS Flank > AE Rear.
Or maybe go hybrid and boost all by going full Flank or full Rear.
Now what if we model after DRG old positionals?
Old positionals for DRG were characteristic of the fact that if they didn't land from where they were meant to, things wouldn't start at all... but if we get double positionals for this:
Spinning Edge Flank -> All following Weaponskills will have a Huton +3s effect added to them.
Spinning Edge Rear -> All following Weaponskills will have a DE + 4s and DoTs + 1s effect added to them.
As in SE Flank would make GS, AE and even Mutilate have a Huton +3s effect but will nor restrict them to be done on the Flank side. So long SE did hit on the Flank.
And SE Rear would make GS, AE and even Mutilate have a DE +4s and DoTs + 1s effect but will not restrict them to be done on the Rear side. So long SE did hit on the Rear.
Similar to a Stance Dance.
Both examples could effectively delay the need to refresh either Huton, Dancing Edge or the DoTs by a few seconds. Which would then in converse allow the use of winding in more Aeolian Edges and... hell, even new GCDs...
Again, this is just an example of how I think Positional would be fun for NIN, since I like tricky plays. If they were to affect only the Potency of the Weaponskills then that would be sad and boring.