There are other mounts for raids that I didn't include, like WOW Burning Crusade Classic Gold Glacial Tidestorm from mythic Jaina, which is a reskin of the shaman mount Ny'alotha Allseer, from mythical N'Zoth which is just an reskin of a jellyfish mount.
It's dependent on what you mean when you say "reskin". The N'Zoth mythic mount is simply the mount for jellyfish, Jaina mythic is the mount for shamans, Gul'dan's mythic is grumpus mount (I think at least) Shackled Ur'zul in mythic Argus is (I think) the skeletal gryphon mount that DKs get.
Archimonde's Felsteel Anihilator was the only mythic mount that I can remember as being "original at the time". The Sylvanas mythic Mount is also a brand new type.
It seems like an recolour is usually a swap of textures? I'm not sure what this meaning of this term is. It's definitely much simpler to alter the colors than any other, they essentially just have to make use of a slider alter the colors of the image and then call it the day.
that's why it's upsetting to see so many armors just being recolours since you could just put an intern on that and it would typically be good. Recolors must absolutely be a slider option that players have access to..
I was uncertain that a recolour is also a reskin. I always considered reskins to be exactly the same animations with an entirely different style while a recolour can be an refractive colour.
Yes, LFR as well as heroic are all the same set , with color changes, and it is only the mythic set (and some pieces at that) which is different.
Reskining is the process of using the same skeleton, but adds an additional skin on top. It can be pretty much exactly the same as colors that are recolored (if the skin changes aren't significant enough). These can be added with additional bits and bobs.
The Iron Skyreaver is an rylak mount skeleton, but it adds some highly loud jet thrusters its wings and armor. It's an reskin.
Recolor is the term used to describe the differences between the Black Drake mount (10 Sarth) or the Bronze Drake mount (10 CoS). The cheap WOW TBC Gold model and skin are similar, with the exception of color. Experiment 12B is a recoloring of the base drake mount.