Nearly every modern 3D chest piece with overhang puts everything from the waist down into the leg slot. Why?
Look, I get that there are sets where the lower part of the coat can be used to create a good transmog set, like the priest Aberrus set or the Warden set from the Trading Post achievement to name a few that I personally see as appropriate.
But the overhang from the coat of the Castle Nathria leather set or the male peasant set back then from the trading post…really? I refunded the peasant set, because of this very reason. Tenders are already rare as it is, so I will not keep a set that I will never use. They only make sense with the chest/leg combination. Items like these make it nigh impossible to mix the pants with other chest items for a custom transmog set, because they literally have a skirt attached.
If I remember correctly back in the day the worgen heritage armor was the first ensemble where the coat overhang was part of the leg slot and it was a technical design limit. That is clearly not the case anymore, because there are already some items like the Ashvane Longcoat or the Undermine trenchcoats that are chest slot only.
And now I fear this will happen again with the new Gilneas sets that are added in 12.0.5 and introduced somewhere down the line in the future. They look absolutely gorgeous and are completely my style. I would be gutted, if the longcoat is again a chest and leg slot combination. It just would not make sense here from a fashion point of view.
At the very least remove the skirt from the pants and create 2 chestpieces in the ensemble, one with the overhang attached and one without.