The firehawk mounts (Pureblood, Felfire, and Corrupted) whose models originated from Cataclysm have had a few things broken since the pre-patch for TWW.
The head model seems to be missing entirely, so only armor is visible in that area
The fire effect is clipping through other effects of the model, becoming visible almost all the time even when it is supposed to be physically underneath other effects such as the fire trail off the trailing edge of each wing
At least one of these issues was reported in beta.
Just to add my post from general disussion here in bug report (hopefully blizz sees ist ):
The firehawk and other mounts are bugged or missing visual effects after the mapping/reskinning/rerigging whatever you wanna call it. I reported this in beta several times and made posts on eu forums, but it looks like its not on priority list at the moment. But i hope it will be fixed soon, too.
I made several pictures from before 11.0 and after:
https://ibb.co/hdvqLz3
From my point of view and with my 3D modeling experience, the main problem are the twisted texture surfaces for the firehawk’s flames.
To explain this a little more deeply: The flames/feathers consist of animated textures that lie on flat but curved polygon surfaces. These polygons are attached to the model like feathers and form the body shell through different orientations. As you can clearly see in the side view in the linked picture, the surfaces are no longer arranged around the body but are aligned horizontally/flat to the ground. The texture therefore points upwards. Because they are only flat surfaces, you only see the line from the side. The body shell is therefore no longer visible. From the view from above, you can also clearly see how this visually creates a square-looking surface on the mount’s neck instead of tapering towards the head. The textures appear more detailed and darker because more surfaces and thus textures overlap. The wings and tail are also heavily affected by this, which also causes clipping. This makes the model look “plucked”.
It is clearly a bug that occurred during the adjustment for dynamic flying. What you personally find “nicer” is excluded from this and up to you.
Oh nice, they did! The effect still looks a little different than the pre-11.0 model, but at least all of the old wingtip effects are now properly displaying over the new core effects.
):