Yo.
Just thought of an idea how to implement for Paladin/Crusader.
The Paladin/Crusader Start of as a mercenary working for hire to survive after no angel is hearing their prays for 50 years they nearly lost all their faith in Zakarum. So the Paladin/Crusader rely on his/her Combat prowness instead. So all their holy powers are locked for the time being as the story progress. As we all know Inarius will play some part of the story, probably rescue him. (Not that I know how the story plays out) Once Inarius is saved he recognise that the paladin/crusader is a servant of the Zakarum and that the crusader has lost his connection to the angels. Inarius decide to help the Paladin/Crusader find his/her faith again and helps him/her in combat by bringing him/her holy powers again, Will even fight side by side with the Paladin/Crusader as an ultimate skill. thus Making the player a fully Paladin/Crusader and brings hope to Sanctuary again where ever he/she goes.
Also would it not be cool if in expansion we go to the high heaven. Get them to open the door and get the angels to help out and the Paladin/Crusader can choose one of the council members of the Angiris Council to fight with the Paladin/Crusader. That one of the council brings holy fire, another more defensive powers etc etc or have Imperius come down and wreaks the place, grabs one of the demons throat, flying up in the air and slams the demon to the ground, causing a rupture into the ground. That the player has the option to choose an angel that lends its power to the Paladin/Crusader and also fight side by side with the Paladin/Crusader.
For the player to get the Angiris Council to Listen them. They will have to fight Imperius himself as he only sees humans as demon spawn and never trusted humans. You will have to defeat Imperius in Mortal Combat as Imperius will throw everything at you and you get to see how powerful Imperius really is. After defeating him, you will gain respect from Imperius. And the angels will agree to help the humans. Could be a little side story only for the Paladin/Crusader to gain more holy power after the player have rescued Inarius. That Inarius knows of an old ancient secret way into the High heavens.