I personally don't see this working at all. I HIGHLY doubt Dana White's gonna let one of his top 5 Heavy Weights make a return to the WWE and lose. A good amount of UFC fan's hate the WWE and think its a joke.. How will they feel if their former heavy weight champion returned for one night and lost.. Brock nor Undertaker will want to lose, and its obvious Taker would win.
Brock shouldn't return to WWE till he's finished with the UFC, in less he want's to be a complete joke in the UFC.
I don't want see Brock back in the square circle, he has a new life. We can't live in the past.