#4 Seth Rollins (Intercontinental Champion)
There are two reasons why Seth Rollins is not on the No.2 spot. The first reason is that we can't start counting his title reign from Wrestlemania as he lost the belt to Ziggler.
Eventually, he did regain it, but we can't count it as one title reign. Secondly, I believe that since he regained the IC title, the title itself has never been the main focus. The main focus has always been The Shield.
Since winning the title at SummerSlam, he was involved with the Shield in one way or the other. First, the feud against Strowman, Ziggler and McIntyre was the main focus, and as soon as the afore-mentioned group disbanded, Reigns had to step away from the WWE.
On the same night, Ambrose turned heel. Although their bout at TLC will be for the IC Championship, it is not the main focus of the rivalry.
If any other man had been holding the IC title, perhaps he would have been lower on the list. But Rollins' performance as the workhorse of Monday Night Raw has nonetheless elevated the title. Hence the No. 4 spot.