2.) There's a certain implication that he probably wouldn't be able to do it again because he was only able to summon the strength to do it this time due to the uncontrollable rage at Lois Lane's death.
Exactly. If he could do this every time, that means he wouldn't have to suffer any consequences. He could just reverse whatever went wrong. I'd rather have the whole "Earth spinning" thing be a one-time thing, brought on only because of his inconsolable loss.