Got my Rathalos Prime! I know someone else had him last thread, but as someone who's been a Monster Hunter fan since MH Freedom way back when, I wanted to give my own review of him.
First thing's first, Rathalos mode. It's the form he's packed in, and the primary reason people would be getting him (nobody's buying him just to own another Optimus Prime). He's an Earthrise Airazor retool, which, as has been pointed out since he was revealed, really does do him a disservice - his beast head is comically tiny, and his tail is far too short and stumpy. On the other hand, though, he has some innovations that make him wear this mold better than any of the previous characters to use it - he takes a leaf out of Filch's book and uses wider, hollower shins so they can fold up much better against his chest, and his robot arms now tuck behind his back and up into the chest cavity behind his head, pulling his elbows inside and leaving only the robot shoulderpads sticking out. He also has pieces that peg into his hips that make them blend better with the rest of his red scales, so from the side, he no longer looks like he's just a dude squatting with his hands at his sides like Airazor, Terrorsaur and Filch did. His wings have decent articulation (his wing claws can't touch the ground, but in-game Rathalos actually just runs around like a chicken with his arms tucked into his sides anyway, so the range of motion here is actually accurate), and while you can't bend his poisonous tail forward, you can still do his well-known divebombing pose to an extent. I do wish that the joint that his head attaches to was another color (that weird grey is pretty distracting when his mouth is open), and that he had a blast effect port on his lower jaw so you could give him some fire breath (they were able to make it work with Crimsonflame, who's head is even narrower), but it is what it is.