This game needed more naked something if you asked me. Hah.
My husband seemed cool with him, let him go, but also gave me a really grossed out look when it came up that I romanced him.
I'd say there's no accounting for taste, but he DID marry me soooo.
Grossed out? Noooo, Keala, nooo! My husband loves Blackwall almost as much as I do. It has made my life a lot easier; earlier pixel crushes of mine have been met with quite a bit of scorn (that I admittedly found hilarious, but scorn nonetheless) and round the clock mockery of the character in question. I married such an insufferable turd
... 
As for explanations for Blackwall's appeal, like lumbersexual, etc. I dunno! Some of the lumbersexual aesthetic is appealing, but I also see a lot of them in my neighborhood and find them kind of obnoxious.
I'm not a big lit person, but I see Blackwall as falling within the Byronic hero or anti-hero archetype, like Heathcliff in Wuthering Heights or even Jane Eyre's Rochester, and those two characters were my motherf___ing catnip when I was coming of age. I generally like deeds-not-words types who are charismatic and flawed as hell, but in a way that makes it worth sticking around for.