User blog comment:Crimson and Darkness/Volume 25 discussion blog/@comment-5.13.171.192-20180430092626/@comment-28884330-20180503021419

Issei's talent as a dragon is not greater than Vali's. The only mention of something similar is how Issei's straightforward anger has a better compatibilty than Vali just in that regard. This was only in terms of anger and emotion aspect, but there's far more variables to effectively using the Sacred Gear.