User blog comment:Jopjopjop/Volume 18 Spoilers/@comment-74.110.108.150-20140910120029/@comment-1359322-20140912001217

First, You make it sound like Issei is only perverted and strong because he's perverted. Issei is more than just being perverted okay, did he attain the CCQ by being perverted no, he was determined to express his love to Rias, to defeat Sairaorg and overcome the hatred of the past possessors, it's love, determination and hope (for the future). Even though Issei used Rias' breast to unlock the Triana, it was becaused he was frustrated at himself for his lack of strength to protect his friends that the power started to activate. And he definitely didn't use any perverted powers to unlock the Wyvern cause that's from Ddraig and Albion's mutual understanding. And one of the biggest reason to why Issei managed to attain his current strength aside from the Oppai Power, it's because he's the first person to view Ddraig as a being rather than a tool and tries to become stronger by understanding Ddraig.

Second, being perverted at this point ain't gonna help Issei defeat Rizevim or stop 666 from being unsealed. It's gonna take real strength (Not the usual brute strength fighting way of Issei, a more well controlled one) and proper teamwork between DxD in order to do so.