User blog comment:B214/Azazel Cup discussion center/@comment-31137559-20180822161017/@comment-28884330-20180824174219

Not all matches have the same narrative weight. To make Vali vs Dulio have the same narrative weight as Vali vs Tobio, Ishibumi would have to make a complete asspull.

Vali and Tobio only fought off-screen so them "having fought" as you say is not really a valid point, since such a fight is irrelevant as far as the story has gone because the readers have never witnessed it. And the narrative weight is enormous due to the emotional value in the fight, with Vali fighting the long time partners who became his first real family other than his mother and Azazel and his Princess. It also has metaphorical value in the form of coming-of-age appeal.

Dulio having Rudiger and his wish are irrelevant as far as the current narrative goes because that was already heavily explored in Volume 23. Vali's Sacred Gear being a blessing is arguable considering the abuse he underwent, and it's not really related to Dulio's wish. That parallelism you are drawing requires a lot of stretching. The only "valid" point you bring is Vali wanting to fight Dulio, and even that is mostly inconsequential currently due to Vali having DxD L, which outclasses Dulio judging from him having an equal fight with nothing more than partial Pseudo-DxD Issei.

That title would sound better if you removed the Heavenly Dragon part from it, since it doesn't really have any significance to the match-up. Brave Saints vs Lucifer sounds better, and even at that it's not really a strong reason.