Confession: my first playthrough, I was really not feeling Blackwall. My Dwarf Inquisitor found Blackwall a little too serious, even boring, and ended up falling for Sera. I myself was not really keen on Blackwall after meeting him, whereas pre-release, I was excited about him because he seems to be close to my IRL age (40+), and that's rareish in games.
Fast-forward to my current Inquisitor, Lorna. I am now in a constant state of dreamy-eyed "HNNNNNNNGG" around Blackwall, and it's only getting stronger. I am finally realizing that he's an amazing character, with very believable dimensions, and man, what incredible voicework. I really don't know why my first playthrough was so "anti" Blackwall, and I cannot fathom how I ever found him dull. WTH?
Anyway, I might be back to gush. You've been warned. 