Once upon a time, I actually did sort of kind of have alignments, they largely affected demon recruitment.
I hated it because it really messed with the build options in a way I did not appreciate.
At the end of the day, Demon's a combat and dungeon exploration (stop laughing, I know the level gen's crap at the moment*) game, and I'm keeping that forefront in my mind. I'm not opposed to some story/alignment elements be added, but a second swing at them would not be anything that had an effect on progression for example. That doesn't rule out things connected to the relics, it just means it won't be anything that limits what builds you can do while playing that relic, for example.
* - Seriously, I do know.
But, there's only one of me, and it is one of a great many projects left to do