Very good topic. My top 4 would be:
1. Rollins (has size/ wrestling ability, and has shown willingness to take big bumps, needed for matches like HIAC, and TLC title matches at the top level)
2. Cesaro (pound for pound strongest on roster, great wrestler, hasnt been given a chance yet. He can go though)
3a. Rhodes (wrestling pedigree, probably knows the business better then anyone on roster. Size/ "the look" would be only thing holding him back. Can wrestle any type match though)
3b. Barrett (has the size, and talent. Has shown to be injury-prone though, which prevents WWE from pulling trigger on him. Some his fault, some not. Great wrestler though)