Cena will lose the belt at Summerslam to Lesnar. After Brock wins, he should smash that shitty looking belt to bits with a hammer the next night on RAW and bring back the WWE championship design that he wore during his first WWE run.
Take this for what it's worth but supposedly Batista is training and back up to his wrestling weight of 290 and might be looking to make a return to the WWE. He may feud with Lesnar if he comes back. Give me that over Rock/Brock any day.