One time, I wrote a small module inspired by three things 1) T-rexes and dinosaurs on a volcanic island (on the verge of eruption, naturally), ala KingKong movie (wicked), 2) Montezuma + Aztecs as a long-dead (thus, now undead) civilization, in pyramids overgrown over by the jungle, and C), (yes I am aware of changing the numbering scheme), a Cthulhu cult that managed to activate stargate-type portals the aztecs had built to summon their Dear Leader to rip this world a new one.
It was major fun, since when they arrived on the island, it was as a shipwreck (the PCs were essentially pirates looking for the aztec treasures with a magic compass), they found instead of a pristine island, mind-flayers riding T-Rexes in full plate armor and flying on the backs Pterodactyls with headbands of domination to control their mounts. It was insane, wicked fun. Also I did research into the real mayan + aztec religions, what with Xipe Totec and the filth eaters wearing human skin. Imagine skeletons, who were religious, and made a pact with the mind-flayers to do evil unto the nations. It was goooooood.
So yes, I'd love for D&D Next to have fully stated T-Rexes, but regardless, there will be one, who is wearing Full plate, in a future adventure. I watched this show about the Mughal empire where they had entire villages making suits of battle armor for their war elephants. Reality inspires fertile soil for Imagination land.