Push: Joe Hennig. Tried picking a guy who I don't think many people mentioned, he works well in the ring and has improved a ton in the mic since his "Genesis of McGillicutty" promo, could make a good midcard heel if you ask me. Of course, there are many other guys I'd love to see pushed.
Depush: Sheamus. He's been a main eventer for the biggest part of his run in WWE, and his booking as a SD main eventer has bored lots of people, pissed off others and most agree that things shouldn't be like that. Put him in the midcard for a while. Since he's relatively over, it would help the midcard (making it feel like it means something) and probably help the ME scene since Sheamus wouldn't be burying everyone there, which leads me to my new point: this would only work if booked correctly. If Sheamus goes down to the midcard to bury everyone the way he was before winning the Rumble then there's no point. Big Show being depushed while putting talents over could also be an option.
Fire: Khali. Seabs hit the nail on the head: He can barely walk which obviously leads him to being an awful wrestler, his promo skills don't exist so the only two benefits to having him there are that he's big (which lots of other people are, he can easily be replaced) and Indian, which attracts Indian viewers, which could be worked around if they hire an Indian folk who can actually work. Maybe have Khali put him over instead of burying him the way they did to Mahal.