As a Brutosaur owner, I think it should comeback to the vendor for 5million gold and players asking for it to be on Twitch drop or Trading post are asking for an easy way which just cause drama in the communty.
Instead ask for the mount to be back to its original vendor or proper changes to the BMAH rotation and the mount acquisition from there. You’ll get support from some brutosaur owners, because the idea of doing the brutosaur exclusive from BfA came from Devs.
Ask for something more realistic, Brutosaur doesn’t compare to promotion mounts or TCG that were available for only some countries or in a limited quantity.