I've been leveling Arcanist to Summoner/Scholar recently, and thought of the suggestion after messing around for a little bit. With the release of Stormblood, Warrior abilities have been changed to reflect stance requirements now, for example Inner Beast, Steel Cyclone, and Unchained change to their Deliverance counterparts on stance change.

Considering that Arcanist and its counterparts have the ability to control pet abilities through the use of the Obey behavior, and that the ability of your pets can be put on your bar, my suggestion comes down to suggesting pet abilities to have the same behavior as Warrior stance abilities, I.E. Eos's Whispering Dawn, Fey Covenant, and Fey Illumination change to Silent Dusk, Fey Caress, Fey Wind respectively when Selene is summoned, and similar on Summoner and Arcanist.

I understand that changing pet on the fly doesn't happen often, but I'd like to have my cooldown buttons change with it, if possible.