Exactly. Look at the name he took for himself; Solas, it means pride. Please no one think that I am bashing Solas, or hate him. I love this character. I care about his fate. Even though it broke my heart, his romance is my favorite DA romance.
All assumptions, but let's look at what we think he did and how far reaching the consequences are. According to Dalish lore he locked up the Creators. Putting it together from things he himself has said, and what we saw in game; whatever he did is the reason the Dalish are wandering nomads living a life that they think honors their Gods, putting slave markings on their faces. All the rest live in alienages, are treated like less than actual people. There's slaves, some live in servitude. It's a terrible life. (yes I know this is all an assumption when it comes to how much is Solas's fault) How does anyone redeem themselves from that? Really! 
I am by no means downplaying what Blackwall did. His actions had a family murdered. He was a coward. He ran and hid. How is his redemption so less believable than Solas? It's not even on the same scale, I get that, and unfair to compare the two situations as anything even close to equal. One family vs altering the entire world? That's all I am saying. They're both flawed characters, and I am not trying to sway anyone or say that Blackwall deserves more than he has. Just adding some perspective is all. No I don't like Blackwall as a character even close to how much I like Cole and Cass, let alone Solas. This is my attempt to be a bit objective. In the end if you don't like Blackwall it doesn't even matter anyways.
Sorry I'll stop saying anything more on this stuff. Well I'll try to anyways! 
Hm~ I'm drawing on implications for Solas, but I'm not going to argue he might not be as guilty of the "all about me" attitude as Blackwall - I just find it less likely given how Solas comes off to me? I'm too tired to mentally delve there right now haha~
My main issue with the idea of "redemption" - I don't think Blackwall gains "redemption" because the whole idea of redemption involves some kind of metaphysical balance sheet idea where if your balance sheet tips just the right amount in the right direction you're "redeemed" which is ridiculous - the things you do right never negate the things you do wrong and vice versa. (Ergo I think Blackwall's whole "I must redeem myself" mentality is wrong and false and something he needs to rid himself of - grow as a person, learn from what you've done wrong, but don't go around hunting for redemption that ain't happening mang)
But I'll stop harping on it lest I get annoying~ Let's just say Ihateredemptionarcswithapassion
/Edit I don't exactly have a rosy picture of Solas either - I just don't think he and Blackwall are that similar beneath the surface. If anything, I feel like Solas' regret is more of a "ohshit this did not turn out the way I thought it would how2fix" whereas Blackwall is more of a "I am such a badbadbad person for doing that what can I do to redeem myself" which is why Blackwall bothers me more. Solas might, honestly, be a much worse person who did bad things and doesn't even care - as long as his goals are achieved - but I have a pet peeve against Blackwall's "I must redeem myself" train of thought (I love Cole - Cole tells it like it is)
/Edit2 Basically what I want to say to Blackwall (scream at him sometimes really) is: do good things because they are good things to do, not because you're hoping somewhere in the hazy Maker-glory-shiny-heavens, these innocent murdered kids are looking down on you and deciding you've done enough good that they can forgive you. Stop doing things for your own soul and start doing them for others. I know he's getting there, but I know for a fact he's not there yet and I just want to yank him by the leash until he's completely out of that muck of self pity and looking at the world and other people as a place/people with their own agencies who are not there to fulfill his redemption.
/Edit3 My other huge pet peeve is the savior complex (in case no one has guessed) 