Cena also got Kenny Dykstra shunned from the WWE. I heard all kinds of stories about that, I guess Kenny and Mickie James were engaged to get married, Cena started fucking Mickie behind Kenny's back. Kenny got pissed off and defended himself, Cena worked his magic and Kenny ended up getting jobbed out and then fired.
Also read a bunch of reports about Cena lobbying to get Randy Orton fired after his last suspension, but Orton is too big of a star himself for Cena to fuck over.