I really loved how the finale positioned Louis as such a better man than Armand. Armand demanded an apology from him at machete-point for everything. For "abandoning" him, for not loving him enough, for not throwing himself as fuel into the bottomless hole of Armand's heart. These are all apologies Armand feels like he's owed! How could you do this to him! He is so Small and so helpless and empty, all he asked for was everything! Give him the apology he deserves!!
Armand has been walking around this entire season reading out a litany of apologies that he's written down Exactly Right, skipping the crimes that don't register to him as crimes, or positioning his sins as understandable and therefore possible to simply reiterate according to the AA style guide. He does it perfectly and so we're square now, right? That's how forgiveness works? Why are you all still so angry at him??
It's telling that he brought Regina to his apology with Louis, because he knows Louis has his pride and that Louis is right to be angry with him, in a way that's so fresh and so personal that he'll need to grease the wheels a little. So Louis, put your apology in his little slot like he, Armand, did with everyone else and then he, Armand, will feel better. Yes, none of you seem to have felt better after his very good apologies, but surely he will be satisfied! Armand, who does things Correctly.
And then Louis offers sympathy for the single thing that represents his side in their failed relationship, which was not ever broaching the subject of Armand's sexual slavery. That's his regret. He was close enough to Armand - and yes, cared for him enough - to be able to identify where that big clawing hole inside of him comes from. And he never brought it up, and didn't care for Armand like Armand obviously needs, because he didn't want to. Because he was in love with someone else. Because the person Armand actually is is not a person that Louis, with his own needs and feelings, wants to love. No jury in the world would convict him.
You can hear Louis's emotion when he says this. You can hear that it's something he's known for a while, something he dwelt on when they were together and just didn't raise. It's an extorted apology, but one that moves Armand. And it's in such sharp contrast to how Armand read off his papers. Armand made little bullet lists of all the things (he thinks) you could nail him for and disavowed them in hindsight. Louis talked about how their relationship made Armand feel. How it probably still makes him feel.
This is a season that's all about our main characters coming to understand the impact they have on one another, and taking responsibility for the few things they can help, despite their vampiric state and all the suffering they've been through in their own lives. Louis has that capacity. Armand doesn't. Armand doesn't even know that that's an option. He can't conceive of it. Yes, he does things, sometimes very bad and terrible things. But they're not his fault. He's so small.
And I think the show posits that maybe the only way these monsters can make a case for their own souls is to accept fault or failure in their treatment of one another.
Louis knows what he wishes he'd done differently. He hands that to Armand and lets him make of it what he will.