Eddie's entire game doesn't "revolve" around the half guard, he's just proficient at it. He's a submission grappler and not an MMA fighter, I'm pretty sure he knows when and when not it would be appropiate in an MMA enviroment. As far as takedowns go, why waste your energy on something if you're not exactly the best takedown artist in the world? Once again, let's remind you that he competes in "submission grappling". It inevitably goes to the ground.
As far as reinvented techniques go, he implemented the setups for the "twister" and never took credit for coming up with the move. Stop crying and move on.