User blog comment:B214/Shin DxD 1 discussion/@comment-93.132.65.47-20180926201139/@comment-28884330-20180927145433

Azi Dahaka only gave Vali as much trouble as he did because he has many techniques, and also because he could constantly heal, which depleted Vali's stamina efficiently. If he didn't have the ability to heal, he would have gone down much quicker and more easily.

Crom has never been stated to surpass Ddraig and Albion by a lot, and judging from his performance against Vali, this is even more telling. Considering the small margin he has surpassed them by, the abilities of Ddraig and Issei can more than make up for that power difference. And once again, Issei has Ascalon and Ascalon II.

I repeat, there's absolutely no reason to think that Crom held back against Vali. It was not stated, and not even hinted. He fought Vali, had the advantage at close range, but was at a disadvantage at long range, which makes for a balanced outlook. Crom was also much more injured than Vali during their battle.

Vali weaker than Albion in his prime? This has also never been stated. And yes, this accounts for them without counting the abilities of Ddraig and Albion. A showing of this is Fenrir, who was said to be on par with Ddraig and Albion in their prime, then comes Typhon who is equal or superior to Fenrir, and he got shredded by Ddraig due to Ddraig's abilities. This shows how your thought that he surpassed them even with their abilities is wrong. The issue is the same as with Crom, only with Crom being somewhat stronger than Fenrir and Typhon. But a raw power difference of that small magnitude is not nearly enough to beat Boost, Dragon Slayers, etc.